Systems and methods for low overhead  paging

ABSTRACT

Systems and methods for low overhead paging in a wireless communications network are described herein. In some aspects, an apparatus for wireless communication includes a receiver and a processor. The receiver receives a request from a first device. The request indicates a first period of a plurality of periods corresponding to a periodicity for transmitting paging messages. The processor assigns the first device to a group scheduled to receive paging messages at most every first period based on the request and determines a start time for transmitting paging messages to the first device based on schedules for transmitting paging messages to a plurality of other devices. In other aspects, an apparatus for wireless communication includes a processor and memory. The processor derives an information sub-unit from an information unit associated with a paging message, compresses the information sub-unit, and generates a second information unit associated with the method of compression.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims benefit under 35 U.S.C. §119(e) to U.S.Provisional Patent Application No. 61/566,998 entitled “SYSTEMS ANDMETHODS FOR LOW OVERHEAD PAGING” filed on Dec. 5, 2011, the disclosureof which is hereby incorporated by reference in its entirety. Thisapplication additionally claims benefit under 35 U.S.C. §119(e) to U.S.Provisional Patent Application No. 61/589,441 entitled “SYSTEMS ANDMETHODS FOR LOW OVERHEAD PAGING” filed on Jan. 23, 2012, the disclosureof which is hereby incorporated by reference in its entirety. Thisapplication additionally claims benefit under 35 U.S.C. §119(e) to U.S.Provisional Patent Application No. 61/591,836 entitled “SYSTEMS ANDMETHODS FOR LOW OVERHEAD PAGING” filed on Jan. 27, 2012, the disclosureof which is hereby incorporated by reference in its entirety. Thisapplication additionally claims benefit under 35 U.S.C. §119(e) to U.S.Provisional Patent Application No. 61/598,193 entitled “SYSTEMS ANDMETHODS FOR LOW OVERHEAD PAGING” filed on Feb. 13, 2012, the disclosureof which is hereby incorporated by reference in its entirety. Thisapplication additionally claims benefit under 35 U.S.C. §119(e) to U.S.Provisional Patent Application No. 61/605,261 entitled “SYSTEMS ANDMETHODS FOR LOW OVERHEAD PAGING” filed on Mar. 1, 2012, the disclosureof which is hereby incorporated by reference in its entirety.

FIELD

The present application relates generally to wireless communications,and more specifically to systems, methods, and devices for performinglow overhead paging in a wireless communication network.

BACKGROUND

In many telecommunication systems, communications networks are used toexchange messages among several interacting spatially-separated devices.Networks may be classified according to geographic scope, which couldbe, for example, a metropolitan area, a local area, or a personal area.Such networks would be designated respectively as a wide area network(WAN), metropolitan area network (MAN), local area network (LAN),wireless local area network (WLAN), or personal area network (PAN).Networks also differ according to the switching/routing technique usedto interconnect the various network nodes and devices (e.g. circuitswitching vs. packet switching), the type of physical media employed fortransmission (e.g. wired vs. wireless), and the set of communicationprotocols used (e.g. Internet protocol suite, SONET (Synchronous OpticalNetworking), Ethernet, etc.).

Wireless networks are often preferred when the network elements aremobile and thus have dynamic connectivity needs, or if the networkarchitecture is formed in an ad hoc, rather than fixed, topology.Wireless networks employ intangible physical media in an unguidedpropagation mode using electromagnetic waves in the radio, microwave,infra-red, optical, etc. frequency bands. Wireless networksadvantageously facilitate user mobility and rapid field deployment whencompared to fixed wired networks.

Devices in a wireless network may transmit/receive information betweenone another. Devices that are not actively transmitting/receivinginformation in the wireless network may enter a doze state to conservepower and may not actively transmit/receive information. At a latertime, devices in the doze state may again enter an awake state in orderto transmit/receive data, such as paging messages.

SUMMARY

The systems, methods, and devices of the invention each have severalaspects, no single one of which is solely responsible for its desirableattributes. Without limiting the scope of this invention as expressed bythe claims which follow, some features will now be discussed briefly.After considering this discussion, and particularly after reading thesection entitled “Detailed Description” one will understand how thefeatures of this invention provide advantages that include improvedpaging for devices in a wireless network.

One aspect of this disclosure provides an apparatus for wirelesscommunication that includes a receiver and a processor. The receiver isconfigured to receive a request from a first device. The requestindicates a first period of a plurality of periods corresponding to aperiodicity for transmitting paging messages. The processor isconfigured to assign the first device to a group scheduled to receivepaging messages at most every first period based on the request, anddetermine a start time for transmitting paging messages to the firstdevice based on schedules for transmitting paging messages to aplurality of other devices.

The apparatus of the preceding paragraph can include a combination ofone or more of the following features: The processor is furtherconfigured to select the start time based at least in part on a numberof the plurality of other devices that are scheduled to receive pagingmessages at the start time. The schedules for transmitting pagingmessages to the plurality of other devices are determined based onrequests from the plurality of other devices. A transmitter configuredto transmit a response to the first device, the response indicating thestart time. The request comprises a request frame, the request framecomprising a requested interval field configured to indicate the firstperiod, a maximum interval field configured to indicate a maximumperiodicity for receiving paging messages at the first device, and atraffic class field configured to indicate filter constraints fortransmitting paging messages to the first device. The response comprisesa response frame, the response frame comprising a status fieldconfigured to indicate whether the apparatus will transmit pagingmessages to the first device, a granted interval field configured toindicate a granted periodicity for transmitting paging messages to thefirst device, a group field configured to identify the group, a counterfield configured to indicate a number of periods for transmitting pagingmessages until the start time, and an identification field configured touniquely identify the response. The processor is further configured todetermine the start time based on when the plurality of other devicesare configured to transmit polling messages, the polling messagesconfigured to request data buffered at the apparatus. The periodicitycorresponds to a periodicity that the apparatus is configured totransmit a beacon frame comprising a traffic indication map. Each pagingmessage comprises a number of groups field configured to indicate anumber of paged groups and a traffic indication map field configured toindicate whether devices of the paged groups have data buffered at theapparatus, and the processor is further configured to compress datacontents of the traffic indication map field.

Another aspect of this disclosure provides an apparatus that includes aprocessor, transmitter, and receiver. The processor is configured toselect a first period of a plurality of periods corresponding to aperiodicity that an access point is configured to transmit pagingmessages. The transmitter is configured to transmit a request to theaccess point, the request indicating selection of the first period. Thereceiver is configured to receive a response from the access point, theresponse indicating assignment of a granted periodicity for receivingpaging messages and a start time for receiving paging messages, thestart time determined by the access point based on schedules fortransmitting paging messages to a plurality of other devices.

The apparatus of the preceding paragraph can include a combination ofone or more of the following features: The response comprises a responseframe, the response frame comprising a status field configured toindicate whether the access point will transmit paging messages to theapparatus, a granted interval field configured to indicate a grantedperiodicity for transmitting paging messages to the apparatus, a groupfield configured to identify an assigned group, a counter fieldconfigured to indicate a number of periods for transmitting pagingmessages until the start time, and an identification field configured touniquely identify the response. The request comprises a request frame,the request frame comprising a requested interval field configured toindicate the first period, a maximum interval field configured toindicate a maximum periodicity for receiving paging messages at theapparatus, and a traffic class field configured to indicate filterconstraints for transmitting paging messages to the apparatus. Theperiodicity corresponds to a periodicity that the access point isconfigured to transmit a beacon frame comprising a traffic indicationmap. Each paging message comprises a number of groups field configuredto indicate a number of paged groups and a traffic indication map fieldconfigured to indicate whether devices of the paged groups have databuffered at the access point, and the processor is further configured todecompress data contents of the traffic indication map field.

One aspect of this disclosure provides a method for wirelesscommunication including: receiving a request from a first device, therequest indicating a first period from a plurality of periodscorresponding to a periodicity for transmitting paging messages;assigning the first device to a group scheduled to receive pagingmessages at most every first period based on the request; anddetermining a start time for transmitting paging messages to the firstdevice based on schedules for transmitting paging messages to aplurality of other devices.

The method of the preceding paragraph can include a combination of oneor more of the following features: The method may include selecting thestart time based at least in part on a number of the plurality of otherdevices that are scheduled to receive paging messages at the start time.The method may include determining the schedules for transmitting pagingmessages to the plurality of other devices based on requests from theplurality of other devices. The method may include transmitting aresponse to the first device, the response indicating the start time.The request comprises a request frame, the request frame comprising arequested interval field configured to indicate the first period, amaximum interval field configured to indicate a maximum periodicity forreceiving paging messages at the first device, and a traffic class fieldconfigured to indicate filter constraints for transmitting pagingmessages to the first device. The response comprises a response frame,the response frame comprising a status field configured to indicatewhether an access point will transmit paging messages to the firstdevice, a granted interval field configured to indicate a grantedperiodicity for transmitting paging messages to the first device, agroup field configured to identify the group, a counter field configuredto indicate a number of periods for transmitting paging messages untilthe start time, and an identification field configured to uniquelyidentify the response. The method may include determining the start timebased on when the plurality of other devices are configured to transmitpolling messages, the polling messages configured to request databuffered at an access point. The periodicity corresponds to aperiodicity for transmitting a beacon frame comprising a trafficindication map. Each paging message comprises a number of groups fieldconfigured to indicate a number of paged groups and a traffic indicationmap field configured to indicate whether devices of the paged groupshave data buffered at an access point, and the method may includecompressing data contents of the traffic indication map field.

Another aspect of this disclosure includes method for wirelesscommunication including: selecting a first period of a plurality ofperiods corresponding to a periodicity that an access point isconfigured to transmit paging messages; transmitting a request to theaccess point, the request indicating selection of the first period; andreceiving a response from the access point, the response indicatingassignment of a granted periodicity for receiving paging messages and astart time for receiving paging messages, the start time determined bythe access point based on schedules for transmitting paging messages toa plurality of other devices.

The method of the preceding paragraph can include a combination of oneor more of the following features: The response comprises a responseframe, the response frame comprising a status field configured toindicate whether the access point will transmit paging messages, agranted interval field configured to indicate a granted periodicity fortransmitting paging messages, a group field configured to identify anassigned group, a counter field configured to indicate a number ofperiods for transmitting paging messages until the start time, and anidentification field configured to uniquely identify the response. Therequest comprises a request frame, the request frame comprising arequested interval field configured to indicate the first period, amaximum interval field configured to indicate a maximum periodicity forreceiving paging messages, and a traffic class field configured toindicate filter constraints for transmitting paging messages. Theperiodicity corresponds to a periodicity that the access point isconfigured to transmit a beacon frame comprising a traffic indicationmap. Each paging message comprises a number of groups field configuredto indicate a number of paged groups and a traffic indication map fieldconfigured to indicate whether devices of the paged groups have databuffered at the access point, and the method may include decompressingdata contents of the traffic indication map field.

One aspect of this disclosure provides an apparatus for wirelesscommunication comprising: means for receiving a request from a firstdevice, the request indicating a first period from a plurality ofperiods corresponding to a periodicity for transmitting paging messages;means for assigning the first device to a group scheduled to receivepaging messages at most every first period based on the request; andmeans for determining a start time for transmitting paging messages tothe first device based on schedules for transmitting paging messages toa plurality of other devices.

Another aspect of this disclosure provides an apparatus for wirelesscommunication comprising: means for selecting a first period of aplurality of periods corresponding to a periodicity that an access pointis configured to transmit paging messages; means for transmitting arequest to the access point, the request indicating selection of thefirst period; and means for receiving a response from the access point,the response indicating assignment of a granted periodicity forreceiving paging messages and a start time for receiving pagingmessages, the start time determined by the access point based onschedules for transmitting paging messages to a plurality of otherdevices.

One aspect of this disclosure provides a non-transitorycomputer-readable medium comprising instructions that when executedcause an apparatus to: receive a request from a first device, therequest indicating a first period from a plurality of periodscorresponding to a periodicity for transmitting paging messages; assignthe first device to a group scheduled to receive paging messages at mostevery first period based on the request; and determine a start time fortransmitting paging messages to the first device based on schedules fortransmitting paging messages to a plurality of other devices.

Another aspect of this disclosure provides a non-transitorycomputer-readable medium comprising instructions that when executedcause an apparatus to: select a first period of a plurality of periodscorresponding to a periodicity that an access point is configured totransmit paging messages; transmit a request to the access point, therequest indicating selection of the first period; and receive a responsefrom the access point, the response indicating assignment of a grantedperiodicity for receiving paging messages and a start time for receivingpaging messages, the start time determined by the access point based onschedules for transmitting paging messages to a plurality of otherdevices.

One aspect of this disclosure provides an apparatus that includes aprocessor and memory. The processor is configured to derive a firstinformation sub-unit from a first information unit associated with apaging message, compress the first information sub-unit according to afirst method of compression to obtain a first compressed informationsub-unit, and generate a second information unit associated with thefirst method of compression. The memory is configured to store the firstcompressed information sub-unit and the second information unit.

The apparatus of the preceding paragraph can include a combination ofone or more of the following features: A transmitter electronicallycoupled to the processor and configured to transmit the paging message,the paging message comprising the first compressed information sub-unitand the second information unit. The paging message comprises a sub-unitlength field configured to indicate a length of the first compressedinformation sub-unit. The processor is further configured to: derive asecond information sub-unit from the first information unit; compressthe second information sub-unit according to a second method ofcompression to obtain a second compressed information sub-unit; andgenerate a third information unit associated with the second method ofcompression. A transmitter electronically coupled to the processor andconfigured to transmit the paging message, the paging message comprisingthe first compressed information sub-unit, the second compressedinformation sub-unit, the second information unit, and the thirdinformation unit. The first method of compression is the same as thesecond method of compression. The second information unit includes anidentification of the first compression method. The second informationunit includes an indication of an offset size associated with the firstcompression method. The second information unit includes an indicationof a cardinality associated with the first information unit. The pagingmessage comprises a sub-unit length field configured to indicate anindividual length of the first compressed information sub-unit and thesecond compressed information sub-unit.

Another aspect of this disclosure provides a method that comprising:deriving a first information sub-unit from a first information unitassociated with a paging message; compressing the first informationsub-unit according to a first method of compression to obtain a firstcompressed information sub-unit; and generating a second informationunit associated with the first method of compression.

The method of the preceding paragraph can include a combination of oneor more of the following features: The method may include transmittingthe paging message, the paging message comprising the first compressedinformation sub-unit and the second information unit. The paging messagecomprises a sub-unit length field configured to indicate a length of thefirst compressed information sub-unit. The method may include: derivinga second information sub-unit from the first information unit;compressing the second information sub-unit according to a second methodof compression to obtain a second compressed information sub-unit; andgenerating a third information unit associated with the second method ofcompression. The method may include transmitting the paging message, thepaging message comprising the first compressed information sub-unit, thesecond compressed information sub-unit, the second information unit, andthe third information unit. The first method of compression is the sameas the second method of compression. The second information unitincludes an identification of the first compression method. The secondinformation unit includes an indication of an offset size associatedwith the first compression method. The second information unit includesan indication of a cardinality associated with the first informationunit. The paging message comprises a sub-unit length field configured toindicate an individual length of the first compressed informationsub-unit and the second compressed information sub-unit.

One aspect of this disclosure provides an apparatus for wirelesscommunication comprising: means for deriving a first informationsub-unit from a first information unit associated with a paging message;means for compressing the first information sub-unit according to afirst method of compression to obtain a first compressed informationsub-unit; and means for generating a second information unit associatedwith the first method of compression.

Another aspect of this disclosure provides a non-transitorycomputer-readable medium comprising instructions that when executedcause an apparatus to: derive a first information sub-unit from a firstinformation unit associated with a paging message; compress the firstinformation sub-unit according to a first method of compression toobtain a first compressed information sub-unit; and generate a secondinformation unit associated with the first method of compression.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows an exemplary wireless communication system in which aspectsof the present disclosure may be employed.

FIG. 2 shows a functional block diagram of an exemplary wireless devicethat may be employed within the wireless communication system of FIG. 1.

FIGS. 3a, 3b, and 3c illustrate a plurality of paging messagestransmitted by an access point to wireless stations in the wirelesscommunication system of FIG. 1.

FIG. 4a illustrates an exemplary paging message of FIG. 3.

FIGS. 4b and 4c illustrate exemplary TIM field contents for theexemplary paging message of FIG. 4 a.

FIG. 5 is a flowchart of a process for determining an operational stateof a wireless device in the wireless communication system of FIG. 1.

FIG. 6 is another functional block diagram of an exemplary wirelessdevice that may be employed within the wireless communication system ofFIG. 1.

FIG. 7 illustrates a frame format for a page setup request message.

FIG. 8 illustrates another frame format for a page setup requestmessage.

FIG. 9 illustrates yet another frame format for a page setup requestmessage.

FIG. 10 illustrates a frame format for a page setup response message.

FIG. 11 illustrates another frame format for a page setup responsemessage.

FIG. 12 illustrates another exemplary paging message.

FIG. 13 illustrates another exemplary paging message.

FIG. 14 is a flowchart of an exemplary process of assigning a periodicschedule for transmitting paging messages.

FIG. 15 is a functional block diagram of an exemplary wireless devicethat may be employed within the wireless communication system of FIG. 1.

FIG. 16 is a flowchart of an exemplary process of requesting a periodicschedule for receiving paging messages.

FIG. 17 is a functional block diagram of an exemplary wireless devicethat may be employed within the wireless communication system of FIG. 1.

FIG. 18 illustrates an exemplary paging message.

FIG. 19 illustrates another exemplary paging message.

FIG. 20 illustrates another exemplary paging message.

FIG. 21 illustrates another exemplary paging message.

FIG. 22 is a flowchart of an exemplary process for wirelesscommunications.

FIG. 23 is a flowchart of another exemplary process for wirelesscommunications.

FIG. 24a illustrates an exemplary compressed paging message.

FIG. 24b illustrates an exemplary structure of the compressed pagingmessage of FIG. 24 a.

FIG. 25a illustrates another exemplary compressed paging message.

FIG. 25b illustrates an exemplary structure of the compressed pagingmessage of FIG. 25 a.

FIG. 26 illustrates a method for compressing the paging message.

FIG. 27a illustrates another method for compressing the paging message.

FIG. 27b illustrates another method for compressing the paging message.

FIG. 28 illustrates a method of receiving a compressed paging message.

FIG. 29 is a functional block diagram of an exemplary wireless devicethat may be employed within the wireless communication system of FIG. 1.

DETAILED DESCRIPTION

Various aspects of the novel systems, apparatuses, and methods aredescribed more fully hereinafter with reference to the accompanyingdrawings. This disclosure may, however, be embodied in many differentforms and should not be construed as limited to any specific structureor function presented throughout this disclosure. Rather, these aspectsare provided so that this disclosure will be thorough and complete, andwill fully convey the scope of the disclosure to those skilled in theart. Based on the teachings herein one skilled in the art shouldappreciate that the scope of the disclosure is intended to cover anyaspect of the novel systems, apparatuses, and methods disclosed herein,whether implemented independently of, or combined with, any other aspectof the invention. For example, an apparatus may be implemented or amethod may be practiced using any number of the aspects set forthherein. In addition, the scope of the invention is intended to coversuch an apparatus or method which is practiced using other structure,functionality, or structure and functionality in addition to or otherthan the various aspects of the invention set forth herein. It should beunderstood that any aspect disclosed herein may be embodied by one ormore elements of a claim.

Although particular aspects are described herein, many variations andpermutations of these aspects fall within the scope of the disclosure.Although some benefits and advantages of the preferred aspects arementioned, the scope of the disclosure is not intended to be limited toparticular benefits, uses, or objectives. Rather, aspects of thedisclosure are intended to be broadly applicable to different wirelesstechnologies, system configurations, networks, and transmissionprotocols, some of which are illustrated by way of example in thefigures and in the following description of the preferred aspects. Thedetailed description and drawings are merely illustrative of thedisclosure rather than limiting, the scope of the disclosure beingdefined by the appended claims and equivalents thereof.

Popular wireless network technologies may include various types ofwireless local area networks (WLANs). A WLAN may be used to interconnectnearby devices together, employing widely used networking protocols. Thevarious aspects described herein may apply to any communicationstandard, such as a wireless protocol.

In some aspects, wireless signals in a sub-gigahertz band may betransmitted according to the 802.11ah protocol using orthogonalfrequency-division multiplexing (OFDM), direct-sequence spread spectrum(DSSS) communications, a combination of OFDM and DSSS communications, orother schemes. Implementations of the 802.11ah protocol may be used forsensors, metering, and smart grid networks. Advantageously, aspects ofcertain devices implementing the 802.11ah protocol may consume lesspower than devices implementing other wireless protocols, and/or may beused to transmit wireless signals across a relatively long range, forexample about one kilometer or longer.

In some implementations, a WLAN includes various devices which are thecomponents that access the wireless network. For example, there may betwo types of devices: access points (“APs”) and clients (also referredto as stations, or “STAs”). In general, an AP may serve as a hub or basestation for the WLAN and an STA serves as a user of the WLAN. Forexample, an STA may be a laptop computer, a personal digital assistant(PDA), a mobile phone, etc. In an example, an STA connects to an AP viaa WiFi (e.g., IEEE 802.11 protocol such as 802.11ah) compliant wirelesslink to obtain general connectivity to the Internet or to other widearea networks. In some implementations an STA may also be used as an AP.

An access point (“AP”) may also comprise, be implemented as, or known asa NodeB, Radio Network Controller (“RNC”), eNodeB, Base StationController (“BSC”), Base Transceiver Station (“BTS”), Base Station(“BS”), Transceiver Function (“TF”), Radio Router, Radio Transceiver, orsome other terminology.

A station “STA” may also comprise, be implemented as, or known as anaccess terminal (“AT”), a subscriber station, a subscriber unit, amobile station, a remote station, a remote terminal, a user terminal, auser agent, a user device, user equipment, or some other terminology. Insome implementations an access terminal may comprise a cellulartelephone, a cordless telephone, a Session Initiation Protocol (“SIP”)phone, a wireless local loop (“WLL”) station, a personal digitalassistant (“PDA”), a handheld device having wireless connectioncapability, or some other suitable processing device connected to awireless modem. Accordingly, one or more aspects taught herein may beincorporated into a phone (e.g., a cellular phone or smartphone), acomputer (e.g., a laptop), a portable communication device, a headset, aportable computing device (e.g., a personal data assistant), anentertainment device (e.g., a music or video device, or a satelliteradio), a gaming device or system, a global positioning system device,or any other suitable device that is configured to communicate via awireless medium.

As discussed above, certain of the devices described herein mayimplement the 802.11ah standard, for example. Such devices, whether usedas an STA or AP or other device, may be used for smart metering or in asmart grid network. Such devices may provide sensor applications or beused in home automation. The devices may instead or in addition be usedin a healthcare context, for example for personal healthcare. They mayalso be used for surveillance, to enable extended-range Internetconnectivity (e.g. for use with hotspots), or to implementmachine-to-machine communications.

FIG. 1 shows an exemplary wireless communication system 100 in whichaspects of the present disclosure may be employed. The wirelesscommunication system 100 may operate pursuant to a wireless standard,for example the 802.11ah standard. The wireless communication system 100may include an AP 104, which communicates with STAs 106.

A variety of processes and methods may be used for transmissions in thewireless communication system 100 between the AP 104 and the STAs 106.For example, signals may be sent and received between the AP 104 and theSTAs 106 in accordance with OFDM/OFDMA techniques. If this is the case,the wireless communication system 100 may be referred to as anOFDM/OFDMA system. Alternatively, signals may be sent and receivedbetween the AP 104 and the STAs 106 in accordance with CDMA techniques.If this is the case, the wireless communication system 100 may bereferred to as a CDMA system.

A communication link that facilitates transmission from the AP 104 toone or more of the STAs 106 may be referred to as a downlink (DL) 108,and a communication link that facilitates transmission from one or moreof the STAs 106 to the AP 104 may be referred to as an uplink (UL) 110.Alternatively, a downlink 108 may be referred to as a forward link or aforward channel, and an uplink 110 may be referred to as a reverse linkor a reverse channel. In some aspects, DL communications may includeunicast traffic indications.

The AP 104 may act as a base station and provide wireless communicationcoverage in a basic service area (BSA) 102. The AP 104 along with theSTAs 106 associated with the AP 104 and that use the AP 104 forcommunication may be referred to as a basic service set (BSS). It shouldbe noted that the wireless communication system 100 may not have acentral AP 104, but rather may function as a peer-to-peer networkbetween the STAs 106. Accordingly, the functions of the AP 104 describedherein may alternatively be performed by one or more of the STAs 106.

The AP 104 may transmit a beacon signal (or simply a “beacon”), via acommunication link such as the downlink 108, to other nodes STAs 106 ofthe system 100, which may help the other nodes STAs 106 to synchronizetheir timing with the AP 104, or which may provide other information orfunctionality. Such beacons may be transmitted periodically. In oneaspect, the period between successive transmissions may be referred toas a superframe. Transmission of a beacon may be divided into a numberof groups or intervals. In one aspect, the beacon may include, but isnot limited to, such information as timestamp information to set acommon clock, a peer-to-peer network identifier, a device identifier,capability information, a superframe duration, transmission directioninformation, reception direction information, a neighbor list, and/or anextended neighbor list, some of which are described in additional detailbelow. Thus, a beacon may include information both common (e.g. shared)amongst several devices, and information specific to a given device.

In some aspects, a STA 106 may be required to associate with the AP 104in order to send communications to and/or receive communications fromthe AP 104. In one aspect, information for associating is included in abeacon broadcast by the AP 104. To receive such a beacon, the STA 106may, for example, perform a broad coverage search over a coverageregion. A search may also be performed by the STA 106 by sweeping acoverage region in a lighthouse fashion, for example. After receivingthe information for associating, the STA 106 may transmit a referencesignal, such as an association probe or request, to the AP 104. In someaspects, the AP 104 may use backhaul services, for example, tocommunicate with a larger network, such as the Internet or a publicswitched telephone network (PSTN).

FIG. 2 shows an exemplary functional block diagram of a wireless device202 that may be employed within the wireless communication system 100 ofFIG. 1. The wireless device 202 is an example of a device that may beconfigured to implement the various methods described herein. Forexample, the wireless device 202 may comprise the AP 104 or one of theSTAs 106.

The wireless device 202 may include a processor 204 which controlsoperation of the wireless device 202. The processor 204 may also bereferred to as a central processing unit (CPU). Memory 206, which mayinclude both read-only memory (ROM) and random access memory (RAM), mayprovide instructions and data to the processor 204. A portion of thememory 206 may also include non-volatile random access memory (NVRAM).The processor 204 typically performs logical and arithmetic operationsbased on program instructions stored within the memory 206. Theinstructions in the memory 206 may be executable to implement themethods described herein.

The processor 204 may comprise or be a component of a processing systemimplemented with one or more processors. The one or more processors maybe implemented with any combination of general-purpose microprocessors,microcontrollers, digital signal processors (DSPs), field programmablegate array (FPGAs), programmable logic devices (PLDs), controllers,state machines, gated logic, discrete hardware components, dedicatedhardware finite state machines, or any other suitable entities that canperform calculations or other manipulations of information.

The processing system may also include machine-readable media forstoring software. Software shall be construed broadly to mean any typeof instructions, whether referred to as software, firmware, middleware,microcode, hardware description language, or otherwise. Instructions mayinclude code (e.g., in source code format, binary code format,executable code format, or any other suitable format of code). Theinstructions, when executed by the one or more processors, cause theprocessing system to perform the various functions described herein.

The wireless device 202 may also include a housing 208 that may includea transmitter 210 and/or a receiver 212 to allow transmission andreception of data between the wireless device 202 and a remote location.The transmitter 210 and receiver 212 may be combined into a transceiver214. An antenna 216 may be attached to the housing 208 and electricallycoupled to the transceiver 214. The wireless device 202 may also include(not shown) multiple transmitters, multiple receivers, multipletransceivers, and/or multiple antennas.

The transmitter 210 may be configured, for example, to wirelesslytransmit messages, which may be referred to as “paging messages” thatare configured to indicate to wireless devices whether or not thewireless devices have traffic pending and buffered at another device asdiscussed below. For example, the transmitter 210 may be configured totransmit paging messages generated by the processor 204, discussedabove. When the wireless device 202 is implemented or used as a STA 106,the processor 204 may be configured to process paging messages. When thewireless device 202 is implemented or used as an AP 104, the processor204 may also be configured to generate paging messages.

The receiver 212 may be configured to wirelessly receive pagingmessages.

The wireless device 202 may also include a signal detector 218 that maybe used in an effort to detect and quantify the level of signalsreceived by the transceiver 214. The signal detector 218 may detect suchsignals as total energy, energy per subcarrier per symbol, powerspectral density and other signals. The wireless device 202 may alsoinclude a digital signal processor (DSP) 220 for use in processingsignals. The DSP 220 may be configured to generate a packet fortransmission. In some aspects, the packet may comprise a physical layerdata unit (PPDU).

The wireless device 202 may further comprise a user interface 222 insome aspects. The user interface 222 may comprise a keypad, amicrophone, a speaker, and/or a display. The user interface 222 mayinclude any element or component that conveys information to a user ofthe wireless device 202 and/or receives input from the user.

The various components of the wireless device 202 may be coupledtogether by a bus system 226. The bus system 226 may include a data bus,for example, as well as a power bus, a control signal bus, and a statussignal bus in addition to the data bus. Those of skill in the art willappreciate the components of the wireless device 202 may be coupledtogether or accept or provide inputs to each other using some othermechanism.

Although a number of separate components are illustrated in FIG. 2,those of skill in the art will recognize that one or more of thecomponents may be combined or commonly implemented. For example, theprocessor 204 may be used to implement not only the functionalitydescribed above with respect to the processor 204, but also to implementthe functionality described above with respect to the signal detector218 and/or the DSP 220. Further, each of the components illustrated inFIG. 2 may be implemented using a plurality of separate elements.

The wireless device 202 may comprise an AP 104 or an STA 106, and may beused to transmit and/or receive communications including pagingmessages. That is, either AP 104 or STA 106 may serve as transmitter orreceiver devices of paging messages. Certain aspects contemplate signaldetector 218 being used by software running on memory 206 and processor204 to detect the presence of a transmitter or receiver.

The STA 106 may have a plurality of operational modes. For example, theSTA 106 may have a first operational mode referred to as an active mode.In the active mode, the STA 106 may always be in an “awake” state andactively transmit/receive data with the AP 104. Further, the STA 106 mayhave a second operational mode referred to as a power save mode. In thepower save mode, the STA 106 may be in the “awake” state or a “doze” or“sleep” state where the STA 106 does not actively transmit/receive datawith the AP 104. For example, the receiver 212 and possibly DSP 220 andsignal detector 218 of the STA 106 may operate using reduced powerconsumption in the doze state. Further, in the power save mode, the STA106 may occasionally enter the awake state to listen to messages fromthe AP 104 (e.g., paging messages) that indicate to the STA 106 whetheror not the STA 106 needs to “wake up” (e.g., enter the awake state) at acertain time so as to be able to transmit/receive data with the AP 104.

Accordingly, in certain wireless communication systems 100, the AP 104may transmit paging messages to a plurality of STAs 106 in a power savemode in the same network as the AP 104, indicating whether or not theSTAs 106 need to be in an awake state or a doze state. For example, ifan STA 106 determines it is not being paged it may remain in a dozestate. Alternatively, if the STA 106 determines it may be paged, the STA106 may enter an awake state for a certain period of time to receive thepage and further determine when to be in an awake state based on thepage. Further, the STA 106 may stay in the awake state for a certainperiod of time after receiving the page. In another example, the STA 106may be configured to function in other ways when being paged or notbeing paged that are consistent with this disclosure. For example, thepage may indicate that the STA 106 should enter an awake state for acertain period of time because the AP 104 has data to transmit to theSTA 106. The STA 106 may poll the AP 104 for data by sending the AP 104a polling message when in the awake state for the period of time. Inresponse to the polling message, the AP 104 may transmit the data to theSTA 106.

In some aspects, paging messages may comprise a bitmap (not shown inthis figure), such as a traffic identification map (TIM). In certainsuch aspects, the bitmap may comprise a number of bits. These pagingmessages may be sent from the AP 104 to STAs 106 in a beacon or a TIMframe. Each bit in the bitmap may correspond to a particular STA 106 ofa plurality of STAs 106, and the value of each bit (e.g., 0 or 1) mayindicate whether the particular STA 106 has traffic pending and bufferedat the AP 104. Accordingly, the size of the bitmap may be directlyproportional to the number of STAs 106 in the wireless communicationssystem 100. Therefore, a large number of STAs 106 in the wirelesscommunications system 100 may result in a large bitmap. Therefore, apaging message, and in some cases the beacon or TIM frame including thepaging message, may be quite large, requiring a great deal of bandwidthto transmit. Further, each STA 106 may need to listen to the entirepaging message, and in some cases the beacon or TIM frame including thepaging message, in order to determine whether the STA 106 may havetraffic pending and buffered at the AP 104. Accordingly, certain aspectsdiscussed herein relate to techniques for low overhead paging, wherebythe STAs 106 selectively decode or listen to only certain pagingmessages from the AP 104.

In certain aspects related to techniques for low overhead paging, eachSTA 106 of the plurality of STAs 106 in the wireless communicationsystem 100 is assigned at least one power save identifier (PS ID). Insome aspects, the PS ID may be the association ID (AID) of the STA 106(e.g., a local unique identifier may be assigned by the AP 104 atassociation). Each STA 106 may be assigned one or more such PS IDs.Further, a single PS ID may be assigned to one or more STAs 106.Accordingly, one or more STAs 106 may be addressed by a given PS ID.Further, a given STA 106 may be addressed by one or more PS IDs. In someaspects, the PS IDs may be assigned to STAs 106 during initialization ofeach STA 106 (e.g., at the time of manufacture of the STA 106, at thefirst run time of the STA 106, when an STA 106 join a new wirelessnetwork such as wireless communication system 100, etc.). In someaspects, the PS IDs may be assigned or additionally revised, such asthrough communication with other devices in the wireless communicationsystem 100, such as the AP 104. In some aspects, the AP 104 maydetermine or assign PS IDs for the STAs 106 associated with the AP 104and transmit messages indicative of the PS IDs to the STAs 106.

All of the PS IDs assigned to the STAs 106 in the wireless communicationsystem 100 may be referred to as a set of PS IDs for the wirelesscommunication system 100 (or alternatively for the AP 104). This set ofPS IDs may be divided into a plurality of PS ID subsets, each subsetincluding one or more of the PS IDs in the set of PS IDs. These PS IDsubsets may be disjoint or overlapping, meaning that in certain aspectsa plurality of the PS ID subsets may include the same PS ID, and incertain aspects one subset may include a PS ID that another subset doesnot include. Further, the PS ID subsets may be of the same or differentsizes, meaning they contain the same or different numbers of PS IDs.Further, some PS ID subsets may include a continuous interval of PS IDs(such as a sequential series of PS IDs), while some PS ID subsets mayinclude PS IDs that do not form a continuous interval. In one aspect, aPS ID subset may include the entire set of PS IDs. Such a subset may bereferred to as a broadcast PS ID subset. In certain aspects, similar tohow the STA 106 may be assigned a PS ID so that the STA 106 is aware ofits PS ID as discussed above, the STA 106 may be assigned or giveninformation to identify the PS ID subsets the STA 106 is associatedwith.

In some aspects, the PS ID subsets may be assigned to STAs 106 duringinitialization of each STA 106 (e.g., at the time of manufacture of theSTA 106, at the first run time of the STA 106, when an STA 106 join anew wireless network such as wireless communication system 100, etc.).In some aspects, the PS ID subsets may be assigned or additionallyrevised, such as through communication with other devices in thewireless communication system 100, such as the AP 104. In some aspects,the AP 104 may determine or assign PS ID subsets for the STAs 106associated with the AP 104 and transmit messages indicative of the PS IDsubsets to the STAs 106. In some aspects, the STA 106 may send a requestto the AP 104 to join particular PS ID subset group based on certainattributes of the subsets. For a non-limiting example, the STA 106 mayrequest to join a particular PS ID subset group based on the beacon orTIM period that the STA 106 wishes to receive DL unicast trafficindications. As another non-limiting example, the STA 106 may request tojoin a PS ID subset group to receive traffic that matches particularfilter constraints.

The AP 104 may utilize the PS ID and PS ID subsets along with pagingmessages as discussed below to enable the STAs 106 to selectivelyreceive only certain paging messages at certain intervals from the AP104.

In certain aspects, a STA may have an association identifier (AID). TheAID may be distinct from the one or more PS IDs of the STA. The AID mayidentify the STA within an area such as a BSS, may be used as an addressor a part of an address, and may be shorter than other addresses of theSTA such as an IP address or a MAC address. The AID may be included in aframe to uniquely identify a sender or receiver of a message. Forexample, the AID may be included in a MAC header to identify atransmitting STA when the AID may be used for addressing a frame.Further, a PPDU header may include an AID or a partial AID that may beused as an early indication of an intended receiver of the frame.Advantageously, such a PPDU header may permit early termination ofprocessing a received PPDU that is indicated to be for differentreceiver. In some aspects, the AID may be assigned at initialization ofeach STA (e.g., at manufacture or when a STA joins a wireless network).

A STA may have both an AID and one or more PS IDs as discussed in thisdisclosure. For instance, one PS ID may relate to a power save wake-upschedule or a schedule at which an associated TIM is transmitted by anAP. Further, if the power save wake-up schedule of the STA changes, adifferent PS ID may be assigned to the STA.

FIG. 3a illustrates a plurality of paging messages 302 a transmitted bythe AP 104 to STAs 106 in the wireless communication system 100 ofFIG. 1. As shown, time increases horizontally across the page over thetime axis 304 a. As shown, the AP 104 may be configured to transmit aplurality of paging messages 302 a. The paging messages 302 a may besent in a TIM frame, a beacon, or using some other appropriatesignaling. The STAs 106 may be configured to listen to one or more ofthe paging messages 302 a as follows.

In one aspect, each paging message 302 a may include one or moreidentifiers (e.g., a subset identifier or group identifier) of the PS IDsubset(s) for which the paging message 302 a is intended. In one aspect,the identifier may be a 2 byte field capable of indexing 2^16 PS IDsubsets. In another aspect, the identifier might be included in aphysical layer (PHY) preamble of the paging message 302 a. The STAs 106may be assigned or given information about the identifier(s) that referto PS ID subsets which the STAs 106 are associated with. Accordingly,STAs 106 may receive the paging message 302 a. Using the identifier(s)in the paging message 302 a, the STAs 106 may determine whether thepaging message 302 a is potentially intended for the STA 106. Forexample, if the paging message 302 a includes an identifier for a PS IDsubset the STA 106 is associated with, the STA 106 determines the pagingmessage 302 a is potentially intended for the STA 106. Further, if thepaging message 302 a does not include an identifier for a PS ID subsetthe STA 106 is associated with, the STA 106 determines the pagingmessage 302 a is not intended for the STA 106. In some aspects, theidentifier(s) may be used to determine whether the STA 106 has trafficpending and buffered at the AP 104.

In another aspect, the AP 104 may be configured to transmit N pagingmessages 302 a in sequence (where N is any positive integer), in orderto page the STAs 106 at a given time. Accordingly, each paging message302 a in the sequence may be associated with a sequence number n in theN paging messages (n=1, . . . , N). Each sequence number n may beassociated with one or more PS ID subsets.

Accordingly, the STA 106 may determine the paging message 302 a ispotentially intended for the STA 106 based on the sequence number n ofthe paging message 302 a. For example, if the sequence number n of thepaging message 302 a is associated with a PS ID subset that includes aPS ID of the STA 106, the STA 106 determines the paging message 302 a ispotentially intended for the STA 106. Further, if the sequence number nof the paging message 302 a is not associated with a PS ID subset thatincludes a PS ID of the STA 106, the STA 106 determines the pagingmessage 302 a is not intended for the STA 106.

In certain aspects, similar to how the STA 106 may be assigned a PS IDso that the STA 106 is aware of its PS ID as discussed above, the STA106 may be assigned or given information regarding the associationbetween sequence numbers and PS ID subsets, e.g., the sequence number(s)n of the paging message(s) for the PS ID subset(s) to which STA 106belongs will be transmitted and the STA 106 should listen for. Further,in certain aspects, the assignment of PS ID subsets to sequence numbersmay be performed by a coordinating device of the wireless communicationsystem 100, such as the AP 104. In certain other aspects, PS ID subsetsare associated with a PS ID subset identifier. Further, the STA 106 maydetermine whether a PS ID subset is associated with a sequence number nbased on the PS ID subset identifier. For example, if the value of thePS ID subset identifier of the PS ID subset equals mod(n, 256) the PS IDsubset is associated with the sequence number n. If the value of the PSID subset identifier of the PS ID subset does not equal mod(n, 256) thePS ID subset is not associated with the sequence number n.

Further, the TIM may carry a TIM sequence number (TSN), which may beused by STAs 106 to determine whether the TIM may be intended for aparticular STA. For example, an STA may check if the sum of TSN and aTIM starting offset, modulo by the TIM interval, equals zero. The TIMinterval and TIM starting offset may be different per the STAs. If thecheck results in zero, the STA may determine that the TIM may beintended for the STA. In some aspects, the maximum size of the TSN maybe equal to or larger than the longest TIM interval. In other aspects,the TSN may be smaller, potentially indicating that some TIM size savingmay be lost because STAs may typically sleep longer.

In some aspects, the TIM timing may be derived from the timingsynchronization function (TSF). Accordingly, the TSN may be removed fromthe TIM frame. The TIM broadcast may define a series of target TIMtransmission times (TTTTs). TSF 0 may be a TTTT and a target beacontransmission time (TBTT) and may have a sequence number defined as 0.Subsequent TTTTs may occur every TIM broadcast interval times the beaconinterval. A subset of TTTTs or TBTTs for TIMs that may contain the PS IDof the STA may be defined. TTTT sequence number may equal TTTT dividedby the product of the TIM broadcast interval and beacon interval. TBTTsequence number may equal the TBTT divided by the beacon interval.Accordingly, the TIM interval may be different per the STAs.

In another aspect, the AP 104 may be configured to transmit pagingmessages 302 a at certain times (e.g., at specific time intervals, whichmay repeat periodically and have a periodicity). Accordingly, eachpaging message 302 a may be associated with a particular time interval.Each time interval may be associated with one or more PS ID subsets.

Accordingly, the STA 106 may determine the paging message 302 a ispotentially intended for the STA 106 based on the time interval duringwhich the paging message 302 a is transmitted. For example, if the timeinterval of the paging message 302 a is associated with a PS ID subsetthat includes a PS ID of the STA 106, the STA 106 determines the pagingmessage 302 a is potentially intended for the STA 106. Further, if thetime interval of the paging message 302 a is not associated with a PS IDsubset that includes a PS ID of the STA 106, the STA 106 determines thepaging message 302 a is not intended for the STA 106.

Using the aspects discussed above, the STA 106 may determine whether agiven paging message 302 a is potentially intended for the STA 106. Oncethe STA 106 determines the paging message 302 a is potentially intendedfor the STA 106, the STA 106 may further determine whether the pagingmessage 302 a is actually intended for the STA 106 and, for example,whether the STA 106 has traffic pending and buffered at the AP 104 basedon the content of the paging message 302 a.

Further, in some aspects PS IDs and PS ID subsets may be assigned andformed by the AP 104. The AP 104 may make such assignments andformations in based on information from the STA 106 about when the STA106 requests such pages. This may lead to significant overhead at the AP104 for performing such scheduling to accommodate requests of multipleSTAs 106.

In some aspects, additionally or alternatively, the AP 104 may transmitpaging messages for particular PS IDs or PS ID subsets at specific timeintervals. For example, the paging message 302 a comprising a bitmap ofparticular PS IDs may be transmitted at specific timer intervals.Different paging messages 302 a may include bitmaps for different PS IDsand may be transmitted at different intervals. For example, a firstpaging message 302 a may include a bitmap for a first PS ID subset(e.g., PS IDs 1-32). The first paging message may be transmitted everyone TIM interval. Further, a second paging message 302 a may include abitmap for a second PS ID subset (e.g., PS IDs 33-64). The second pagingmessage may be transmitted every two TIM intervals. Further, a thirdpaging message 302 a may include a bitmap for a third PS ID subset(e.g., PS IDs 65-98). The third paging message may be transmitted everytwo TIM intervals plus in the TIM interval following the every two TIMintervals. An STA 106 may then request a PS ID or inclusion in a groupof PS ID subsets from the AP 104 (e.g., a PS ID in either the first,second, or third PS ID subset) that may be transmitted according to aparticular schedule (e.g., TIM interval schedule). Accordingly, the STA106 can request a particular paging message transmission schedule by ineffect choosing from one of a group of interval schedules. Thisinformation can further be used as a timing source for the STA 106, andreduces overhead at the AP 104.

In certain aspects, similar to how the STA 106 may be assigned a PS IDso that the STA 106 is aware of its PS ID as discussed above, the STA106 may be assigned or given information regarding the associationbetween time intervals and PS ID subsets, e.g., at which timer intervalthe paging message(s) for the PS ID subset(s) to which STA 106 belongswill be transmitted and the STA 106 should listen for. Further, incertain aspects, the assignment of PS ID subsets to time intervals maybe performed by a coordinating device of the wireless communicationsystem 100, such as the AP 104.

FIG. 3b illustrates a plurality of paging messages 302 b transmitted bythe AP 104 to STAs 106 in the wireless communication system 100 ofFIG. 1. As shown, time increases horizontally across the page over thetime axis 304 b. As shown, the AP 104 is configured to transmit aplurality of paging messages 302 b. The paging messages 302 b may besent in a TIM frame. The STAs 106 may be configured to listen to one ormore of the paging messages 302 b as follows.

A first STA (STA1) and a second STA (STA2) may individually transmit arequest message (not shown) to the AP 106. The request message mayinclude a requested interval that the STA1 or STA2 would like to receivepaging messages 302 b from the AP 104, for example. The requestedinterval may be indicated as a multiple of a current TIM interval. TheSTA may request a group with a longer paging messaging period if savingpower is of concern while the STA may request a shorter period iflatency is of concern.

The AP 104 may receive the request message and accordingly assign STA1or STA2 to a time grouping PS ID subset having a request interval thatmatches the requested interval. The time grouping PS ID subset maydetermine the TIM interval in which the members of the PS ID subset mayreceive pages. In addition, the AP 104 may determine a start time tobegin transmitting paging messages, for instance, based on schedules fortransmitting paging messages to other devices, such as a time when anumber of STAs scheduled to receive a paging message is below athreshold or at a minimum over a time period. Additionally oralternatively, the start time may be determined based on when otherdevices are configured to contend to request data buffered at the AP 104by transmitting a polling messages to the AP 104. The AP 104 may selectthe start time in order to optimize a time grouping of STAs to reduceuplink contention and facilitate increased compression of one or moreTIMs in each paging message.

The AP 104 may respond to the request message with a response messageindicating the granted TIM interval during which the STA1 or STA2 mayreceive paging messages from the AP 104. The TIM interval assigned tothe STA may be identified as a multiple of a baseline beacon or TIMinterval and based on a start time. The AP 104 may also indicate a TIMstart time so that the STA1 or STA2 may be aware of the start time ofthe assigned interval. Further, the AP 104 may indicate a PS IDidentifier, PS ID subset identifier, or group identifier so that theSTA1 or STA2 may be aware of the assigned identifier. In some aspects,the AP 104 may use certification testing to ensure that STAs signal theSTAs actual awake schedule, by verifying that the average number ofadditional TIMs between setting a TIM bit and receiving a PS-poll may beclose to zero. In some aspects, when the TSN may be smaller than thelongest TIM interval, the certification may be delayed additional TIMsbefore the PS-poll.

For example, the STA1 may request to be placed in a PS ID subset groupthat may receive paging messages every four TIMs. The STA2 may requestto be placed in a PS ID subset that may receive paging messages everytwo TIMs. The AP 104 may accordingly assign STA1 and STA2 to PS IDsubsets. The AP may provide a TIM start time to STA1 and STA2, so theSTAs may be aware when to awake and begin listening to paging messagesevery scheduled TIM period. As shown in FIG. 3b , the AP may assign astart time so that both STA1 and STA2 may receive paging messages atTIM-1. Thereafter, STA1 and STA2 may awake and listen for pagingmessages every requested TIM interval, which may be every four TIMs forSTA1 and every two TIMs for STA2. In some aspects, STA1 and STA2 mayenter a sleep state during TIM periods where the STAs may choose not tolisten to paging messages.

FIG. 3c illustrates a plurality of paging messages 302 b transmitted bythe AP 104 to STAs 106 in the wireless communication system 100 ofFIG. 1. As shown, time increases horizontally across the page over thetime axis 304 b. In contrast to FIG. 3b , FIG. 3c illustrates a scenariowhere the AP 104 may have assigned STA1 and STA2 separate start TIMtimes. STA1 may be assigned a start time at TIM-1 while STA2 may beassigned a start time at TIM-2. Consequently, both STA1 and STA2 maytransmit during the same TIM period less often than may be the case inFIG. 3b . The AP 104 may use flexibility in assigning TIM start times tooptimize time grouping, reduce contention, or enable compression ofTIMs, for example.

FIG. 4a illustrates an exemplary paging message frame 302, such aspaging message 302 a, 302 b, or 302 c. The paging message frame 302 mayinclude a category field 405, action field 410, check beacon field 415,timestamp field 420, and TIM field 425. The size in octets of thecategory field, action field, check beacon field, and timestamp fieldmay be 1, 1, 2-4, and 1-2, respectively. As shown, the paging messageframe 302 may include a TIM field of N bits (where N is any positiveinteger). Each bit in the bitmap may correspond to a particular PS ID orSTA 106 of the STAs 106 that are associated with the PS ID subset(s)associated with the paging message 302 a. Further, the value of each bit(e.g., 0 or 1) may indicate whether the STA 106 may have traffic pendingand buffered at the AP 104.

In certain aspects, similar to how the STA 106 may be assigned a PS IDso that the STA 106 is aware of its PS ID as discussed above, the STA106 may be assigned or given information regarding which bit position(s)in the TIM is associated with the PS ID(s) of the STA 106. For example,associations between bit positions and PS IDs may be set by the AP 104or another device in the wireless communication system 100 andcommunicated to the STA 106 via a message, e.g., a management message.

In other aspects, the PS ID subsets may be assigned PS ID subsetidentifiers that represent a starting address for each of the PS IDs inthe PS ID subset (e.g., if the PS IDs in a PS ID subset are sequential(e.g., 101, 102, 103, 104, etc.) the PS ID subset identifier may be, forexample, 10). Accordingly, the remaining portion of a PS ID that is notpart of the PS ID identifier may be used as an index to the bitmap.Thus, a STA 106 may use associated PS ID(s) and index the bitmap todetermine the intended operation state of the STA 106. For example,based on the above example, if the STA 106 is associated with PS ID 101,it may look for the value of the bit at position 1 in the bitmap todetermine the intended operation state of the STA 106. In some aspects,the bit in position N of the bitmap refers to the STAs 106 with a PSID=N+256*PS ID subset identifier.

FIG. 4b illustrates another exemplary TIM field frame 425. The TIM fieldframe 425 may enable storage of compressed information and include a #groups field 430, group ID field 435, counter field 440, and TIM MAPfield 445. The size in octets of the # groups field 430, group ID field435, and counter field 440 may equal 1, N, and N, respectively (where Nmay be a variable value). This TIM frame may cover all STAs. The #groups field 430 and group ID field 435 may be understood as the # timegrouping PS ID subset groups field and PS ID subset group field,respectively.

FIG. 4c illustrates another exemplary TIM field frame 425. The TIM fieldframe 425 may enable storage of compressed information and include a #groups field 430, group ID1 field 450, counter1 field 455, TIM MAP1field 460, . . . , group IDN field 465, counterN field 470, and TIM MAPNfield 475. The size in octets of the # groups field 430 and group ID 1field 450 may equal 1-2 and 1-2, respectively. This TIM frame maypotentially reuse the same PS ID in TIMs referred to different PS IDsubsets. The # groups field 430 and group ID1/IDN fields may beunderstood as the # time grouping PS ID subset groups field and PS IDsubset groups fields, respectively.

Accordingly, based on the above messaging schemes and techniques, lowoverhead paging may be achieved in the wireless communication network100.

FIG. 5 is a flowchart of a process 500 for determining an operationalstate of a wireless device in the wireless communication system ofFIG. 1. At a block 505, the STA 106 receives a plurality of pagingmessages 302 from the AP 104. At a block 510, the STA 106 determineswhether it should listen to one or more paging messages 302 of theplurality of paging messages 302 based on the techniques describedherein. For example, the STA 106 may make the determination based on aPS ID subset identifier included in the paging message, a sequencenumber n of the paging message, or a time interval the paging messagewas transmitted. If at the block 510, the STA 106 determines it shouldnot listen to one or more paging messages 302, the process 500 ends. Ifat the block 510, the STA 106 determines it should listen to one or morepaging messages 302, the process continues to block 515. At the block515, the STA 106 determines whether the one or more paging messagesidentifies an operational state of the STA 106 based on the techniquesdescribed herein. For example, the STA 106 may make the determinationbased on a bitmap included in the paging message, an identifier of STAs106 included in the paging message, or based on the paging messageincluding no explicit indicator. If at the block 515, the STA 106determines the one or more paging messages does not identify anoperational state of the STA 106, the process 500 ends. If at the block515, the STA 106 determines the one or more paging messages identify anoperational state of the STA 106, the process continues to a step 520.At the step 520, the STA 106 sets its operational state based on the oneor more paging messages as discussed herein.

FIG. 6 is another functional block diagram of an exemplary wirelessdevice 600 that may be employed within the wireless communication system100. The device 600 comprises a receiving module 602 for receiving aplurality of paging messages 302 from another wireless device such asthe AP 104. The receiving module 602 may be configured to perform one ormore of the functions discussed above with respect to the block 505illustrated in FIG. 5. The receiving module 602 may correspond to thereceiver 212. The device 600 further comprises a determining whether tolisten module 604 for determining whether to listen to one or morepaging messages 302 of the plurality of paging messages 302 based on thetechniques described herein. The determining whether to listen module604 may be configured to perform one or more of the functions discussedabove with respect to the block 510 illustrated in FIG. 5. Thedetermining whether to listen module 604 may correspond to the processor204 and/or the DSP 220. The device 600 further comprises a determininginformation module 606 for determining whether the one or more pagingmessages identifies an operational state of the device 600 based on thetechniques described herein. The determining information module 606 maybe configured to perform one or more of the functions discussed abovewith respect to the block 515 illustrated in FIG. 5. The determininginformation module 606 may correspond to the processor 204 and/or theDSP 220. The device 600 further comprises a determining operationalstate module 608 for setting the operational state of the device 600.The determining operational state module 608 may be configured toperform one or more of the functions discussed above with respect to theblock 520 illustrated in FIG. 5. The determining operational statemodule 608 may correspond to the processor 204 and/or the DSP 220.

After receiving a paging message from the AP 104 indicating the AP 104has data for the STA 106, the STA 106 may send a polling message to theAP 104 in order to receive the data from the AP 104. In some aspects,multiple STAs 106 may be paged by the AP 104 as discussed above.Accordingly, the multiple STAs 106 may contend for one or morecommunication channels with the AP 104 in order to transmit the pollingmessages to the AP 104. If several STAs 106 attempt to send pollingmessages to APs such as the AP 104 at the same time, the pollingmessages may collide. Accordingly, in some aspects, the schedule of whenthe STA 106 transmits a polling message may be based on the PS ID of theSTA 106 and/or the PS ID subset(s) to which the STA 106 belongs in orderto reduce the likelihood of collisions as discussed below.

In one aspect, an STA 106 after receiving a paging message indicatingthat the AP 104 has data for the STA 106, may determine when to poll theAP 104 for data based on the PS ID of the STA 106.

For example, as discussed above with respect to FIG. 4a , the pagingmessage 302 a comprises a bitmap of N bits (where N is any positiveinteger). Each bit in the bitmap may correspond to a particular PS ID orSTA 106 of the STAs 106 that are associated with the PS ID subset(s)associated with the paging message 302 a. Further, the value of each bit(e.g., 0 or 1) may indicate the state the corresponding STA 106 withsuch a PS ID should be in (e.g., doze or awake). STAs 106 withassociated with a bit having a value of 1 may determine the AP 104 hasdata to transmit to the STA 106 based on the bit value. Further, the STA106 may determine a time to poll the AP 104 based on the position of thebit corresponding to the STA 106 (i.e., the PS ID of the STA 106) in thebitmap. For example, if the bit associated with the STA 106 is the xbit, the STA 106 may poll the AP 104 at a time based on a function of x(e.g., x*n μs after receiving the paging message 302 a, where n is anypositive integer). In another example, the STA 106 may determine a timeto poll the AP 104 based on a hash function of the PS ID (e.g., a hashof the PS ID and the timestamp of the paging message 302 a).

In another aspect, the STA 106 may determine a time to start contendingfor a channel to transmit a polling message to the AP 104 based on thePS ID, as opposed to determining an exact time to poll the AP 104. Forexample, if the bit associated with the STA 106 is the x bit, the STA106 may contend for the channel at a time based on a function of x(e.g., x*n μs after receiving the paging message 302 a, where n is anypositive integer). In another example, the STA 106 may determine a timeto contend for the channel based on a hash function of the PS ID (e.g.,a hash of the PS ID and the timestamp of the paging message 302 a).

In yet another aspect, the STA 106 may use a backoff counter todetermine when to transmit a polling message to the AP 104. For example,the STA 106 may countdown a backoff counter from a starting value, andwhen the counter reaches 0 the STA 106 may transmit the polling message.The STA 106 may also determine if the channel is active (there istraffic on the channel) or the channel is idle (there is no traffic onthe channel) while counting down. If the channel is active, the STA 106may freeze the countdown until the channel is idle again. The STA 106may determine the starting value of the backoff counter based on the PSID. For example, if the bit associated with the STA 106 is the x bit,the STA 106 may set the backoff counter at a value based on a functionof x (e.g., x*n μs after receiving the paging message 302 a, where n isany positive integer). In another example, the STA 106 may set thebackoff counter at a value based on a hash function of the PS ID (e.g.,a hash of the PS ID and the timestamp of the paging message 302 a).

In some aspects, the STA 106 may determine one or more parameters forthe backoff procedure to transmit a polling message to the AP 104 basedon the paging message and PS ID. As a non-limiting example, the STA 106may set the contention window minimum (CWmin) to a value which maydepend on the number of STAs paged in the paging message; as defined inthe 802.11 backoff procedure, the STA may select a random backoff numberin [0, CWmin] and use that random backoff number for contending andsending the poll message. In certain aspects, the CW may be linear withrespect to the number of paged STAs.

As another non-limiting example, the STA 106 may set the CWmin to avalue which depends on the number of STAs paged and/or on the PS ID inthe paging message. The STA may set a new parameter contention windowstart (CWStart) based on the number of STAs paged in the paging messageand/or on the PS ID. The STA may select a random backoff number in[CWStart, CWmin] and use that random backoff number for contending andsending the poll message.

As another non-limiting example, a STA that may not be paged but wantsto access the medium to send data, may be instructed to set theparameter CWStart to be greater than the total number of STAs paged inthe paging message. A STA that may be paged may be instructed to set theinitial backoff counter to a value derived as discussed above. This mayensure that the initial backoff counter for STAs that may be paged maybe less than the initial backoff counter for STAs that may not be paged.

In some aspects, a STA that may not be paged may be forbidden fromcontending for the medium for a time that may be indicated in the pagingmessage. The time may be indicated in the message (e.g., by using theduration field in the MAC header, or may be derived from the pagingmessage, for instance, as a function of the number of STAs that may bepaged).

The use of PS IDs and PS ID subsets for transmitting and receivingpaging messages as discussed above may be performed through messageexchange between the STAs 106 and the AP 104. The messages may take avariety of different formats. Below are described some of the formatsthat different messages may take and the usage of such messages withrespect to the aspects described herein.

FIG. 7 illustrates a frame format for a message 700 transmitted from theSTA 106 to the AP 104 to setup paging intervals and/or obtain a PS ID,PS ID subset, or PS ID subset group. The message may be referred to as apage setup request message 700. As shown in FIG. 7, the message 700includes a requested interval field 705 comprising 1 byte, maximum (MAX)interval field 710 comprising 1 byte, and traffic class (TCLASS) field715. The requested interval field 705 may indicate a desired multiple ofthe TIM interval that a STA would like to receive paging messages. TheMAX interval field 710 may indicate the maximum acceptable multiple ofthe TIM interval that the STA would like to receive paging messages. TheTCLASS field 715 may indicate a filter for traffic type so that pagingmessages may be referred for traffic that matches filter constraints.

FIG. 8 illustrates a frame format for a message 800 transmitted from theSTA 106 to the AP 104 to setup paging intervals and/or obtain a PS ID.The message may be referred to as a page setup request message 800. Asshown in FIG. 8, the message 800 includes an equipment identifier (EID)field 805 comprising 1 byte, followed by a frame length (LEN) field 810comprising 1 byte, followed by a control field 815 comprising 1 byte,followed by one or more time start fields 820 and time period fields 825each comprising at least 3 bytes. The time start fields 820 indicate atime the STA 106 requests a paging interval to start (a time periodwhere the STA 106 will wake up) and the time period fields 825 indicatea time period for the paging intervals. The times may be indicative of,for example, a number of beacon periods, a number of seconds, a numberof microseconds, a multiple of a number of microseconds, or some otherunit of measure. The control field 815 may indicate the manner in whichthe time is indicated. The response from the AP 104 to the message 800may be a page setup response message or an ACK (e.g., an enhanced ACKwith a time indication).

FIG. 9 illustrates another frame format for a message 900 transmittedfrom the STA 106 to the AP 104 to setup paging intervals and/or obtain aPS ID. The message 900 includes the same fields as the message 800.However, the message 900 further includes a PS ID field 930 comprising 2bytes before each time start field 820 and time period field 825. The PSID field 930 may indicate a specific PS ID the STA 106 requests forscheduling during the associated time start and time period.

FIG. 10 illustrates a frame format for a message 1000 transmitted fromthe AP 104 to the STA 106. The message 1000 may be referred to as a pagesetup response message 1000. The message 1000 may be sent in response toreceipt of the message 700 by the AP 104 from the STA 106. The message1000 may include a status field 1005 comprising 1 byte, granted intervalfield 1010 comprising 1 byte, offset field 1015 comprising 2-4 bytes,group field 1020 comprising 1-2 bytes, counter field 1025 comprising 1-2bytes, flexible unicast service (FUS) ID field 1030 comprising 1 byte,STA ID field 1035, and rate field 1040 comprising 1 byte.

The status field 1005 may indicate accepted, denied, or denied andproposed modification. The granted interval field 1010 may indicate amultiple of the TIM or DTIM. The offset field 1015 may indicate theoffset, in time with respect to the beacon time, of the TIM frame thatmay be used to page the STA. The FUS ID field 1030 may identify theparticular request for future reference in the event changes may bedesired. The group field 1020 indicates a group or time grouping PS IDsubset group that may be used during the paging process. The counterfield 1025 may indicate how many TIM intervals may elapse until thefirst TIM frame related to the group or time grouping PS ID subset. TheSTA ID field 1035 may be used to lookup a page related to the group. Therate field 1040 may indicate whether the TIM related to the request maybe sent at a low or high data bit rate, or both, and the particularrate.

FIG. 11 illustrates a frame format for a message 1100 transmitted fromthe AP 104 to the STA 106. The message 1100 may be referred to as a pagesetup response message 1100. The message 1100 may be sent in response toreceipt of the message 800 or 900 by the AP 104 from the STA 106. Themessage 1100 includes the same fields as the message 900. The controlfield 815 may be used to indicate the status (e.g., denied, accepted) ofthe request for a paging interval and/or PS ID from the STA 106. Thetime start field 820 may indicate the assigned start time for pagingintervals, the time period field 835 may indicate the duration of theinterval, and the PS ID field 930 may indicate the PS ID assigned forthe given start time and interval. The STA 106 may respond to receipt ofthe message 1100 with transmission of an ACK.

FIG. 12 illustrates another exemplary paging message 1200. The pagingmessage 1200 may be similar to the paging message 302 a, 302 b, or 302c. As shown, the paging message 1200 includes an EID field 1205, a LENfield 1210, a control field 1215, and one or more offset fields 1220 andoptionally bitmaps (bmap) 1225. The offset field 1220 may indicate theoffset from the PS ID that the STA 106 should use to index the bitmap1225 as discussed above with respect to FIG. 4a . For example, an offsetof 100 may indicate that the PS ID 101 is at the 1 position (101-100) ofthe bitmap. In another aspect, the offset field may indicate the PS IDsubset that is paged.

FIG. 13 illustrates another exemplary paging message 1300. The pagingmessage 1300 may be similar to the paging message 302 b. As shown, thepaging message 1300 includes an EID field 1305, a LEN field 1310, acontrol field 1315, and one or more PS ID fields 1320 comprising a PS IDlist. Each PS ID field 1320 may include a particular PS ID, and the STA106 may determine the paging message is directed to the STA 106 if itsPS ID is listed in one of the PS ID fields 1320, as discussed above withrespect to FIG. 4 b.

FIG. 14 is a flowchart of an exemplary process 1400 of assigning aperiodic schedule for transmitting paging messages in accordance withaspects of the present disclosure. Although the process 1400 isdescribed below with respect to the elements of the wireless device 202,those having ordinary skill in the art will appreciate that othercomponents may be used to implement one or more of the steps describedherein.

At block 1405, a request may be received from a first device. Therequest may indicate a first period of a plurality of periodscorresponding to a periodicity for transmitting paging messages. Thereceipt of request may be performed by the receiver 212, for example.

At block 1410, the first device may be assigned to a first groupscheduled to receive paging messages at most every first period based onthe request. The assignment may be performed by the processor 204, forexample.

At block 1415, a start time for transmitting paging messages to thefirst device may be determined. The start time may be determined, forinstance, based on schedules for transmitting paging messages to otherdevices. The determination may be performed by the processor 204, forexample.

FIG. 15 is a functional block diagram of an exemplary wireless device1500 that may be employed within the wireless communication system ofFIG. 1. The wireless device 1500 may include a receiver 1505 configuredto receive a request from a first device. The receiver 1505 may beconfigured to perform one or more functions discussed above with respectto block 1405 of FIG. 14. The receiver 1505 may correspond to receiver212. The wireless device 1500 may further include a processor 1510configured to assign the first device to a first group and determine astart time for transmitting paging messages. The processor 1510 may beconfigured to perform one or more functions discussed above with respectto blocks 1410 and 1415 of FIG. 14. The processor 1510 may correspond toprocessor 204.

Moreover, in one aspect, means for receiving a request from a firstdevice may comprise the receiver 1505. In another aspect, means forassigning the first device to a group and determining the start time fortransmitting paging messages to the first device may comprise theprocessor 1510.

FIG. 16 is a flowchart of an exemplary process 1600 of requesting aperiodic schedule for receiving paging messages in accordance withaspects of the present disclosure. Although the process 1600 isdescribed below with respect to the elements of the wireless device 202,those having ordinary skill in the art will appreciate that othercomponents may be used to implement one or more of the steps describedherein.

At block 1605, a first period of a plurality of periods may be selectedbased on corresponding to a periodicity that an access point transmitspaging messages. The selection may be performed by the processor 204,for example.

At block 1610, a request may be transmitted to the access point. Therequest may indicate selection of first period. The transmission may beperformed by the transmitter 210, for example.

At block 1615, a response may be received from the access point. Theresponse may indicate assignment of a granted periodicity for receivingpaging messages and a start time for receiving paging messages. Thestart time may be determined by the access point based on schedules fortransmitting paging messages to other devices. The transmission may beperformed by the transmitter 210, for example.

FIG. 17 is a functional block diagram of an exemplary wireless device1700 that may be employed within the wireless communication system ofFIG. 1. The wireless device 1700 may include a processor 1705 configuredto select a first period of a plurality of periods corresponding to aperiodicity that an access point transmits paging messages. Theprocessor 1705 may be configured to perform one or more functionsdiscussed above with respect to block 1605 of FIG. 16. The processor1705 may correspond to processor 204. The wireless device 1700 mayfurther include a transmitter 1710 configured to transmit the request tothe transmitting device indicating selection of the first period. Thetransmitter 1710 may be configured to perform one or more functionsdiscussed above with respect to block 1610 of FIG. 16. The transmitter1710 may correspond to transmitter 210. The wireless device 1700 mayfurther include a receiver 1715 configured to receive the response fromthe access point. The receiver 1715 may be configured to perform one ormore functions discussed above with respect to block 1615 of FIG. 16.The receiver 1715 may correspond to receiver 212.

Moreover, in one aspect, means for selecting the first period maycomprise the processor 1705. In another aspect, means for transmittingthe request to the access device may comprise the transmitter 1710. Inyet another aspect, means for receiving the response from the accesspoint may comprise the receiver 1715.

FIG. 18 illustrates an exemplary frame format for a paging message 1800transmitted from the AP 104 to the STA 106. The paging message 1800 maybe similar to the paging message 302 a, 302 b, or 302 c. As shown, thepaging message 1800 includes an Information Element identification (IEID) field 1805, a LEN field 1810, a Delivery Traffic Indication Message(DTIM) count field 1815 and a DTIM period field 1820. Each of thesefields may have a size of 1 octet (byte).

Further, as shown, the paging message 1800 includes a bitmap controlfield 1830 and a compressed TIM bitmap field 1840 comprising multiplecompressed TIM bitmap sub-elements. The size of field 1840 may bevariable and may depend on the method of compression that is used, asdiscussed below. The bitmap control field 1830 may have a size of 1octet (byte), and further comprise field 1831 and field 1832. Field 1831is used to indicate the method of compression used for compressing theTIM bitmap sub-elements included in field 1840. The method ofcompression may be the same for all the compressed TIM bitmapsub-elements included in field 1840. The size of field 1831 may dependon the number of possible method of compressions used for compressingthe TIM bitmap sub-elements. By way of example, and not limitation, ifthere are only two possible methods of compressions, a single bit B0 maybe sufficient to indicate which method has been used for compressing theTIM bitmap sub-elements included in field 1840. Field 1840 includes asequence of compressed TIM bitmap sub-elements that have all beencompressed by the method indicated in field 1831.

By way of example, and not limitation, one compression method may be acompression method that operates at a block level, and can be referredto as hierarchical compression. Another method of compression mayinstead be based on a basic bitmap sub-element that may include, forexample, three fields such as an offset field, a bitmap length field anda bitmap field. This method can be referred to as offset compression.More details of such a method are given below.

Field 1832 may be used to indicate the length of the offset field whenthe offset compression method is employed for compressing the TIM bitmapsub-elements included in field 1840. However, it is to be understoodthat field 1832 is not to be limited to a use in conjunction with theoffset compression method as described above, but it may also be usedfor other compression methods that require, for example, an indicationof a length of an offset field. The length of the offset field asindicated by field 1832 may apply to all the sub-elements of included infield 1840. Further, the offset field may indicate an identifier of afirst STA indicated by the sub-element. Such a variable length may beuseful when the maximum offset to be represented has a small value, sothat it can be represented with fewer bits, and hence result in ashorter message. By way of example, and not limitation, the size offield 1832 may depend on the length of the offset, for example up to 3bits as shown in FIG. 18. In certain aspects, field 1832 may be omitted.

In another aspect, the length of the offset field as indicated by field1832 may apply to all sub-elements included in field 1840, except forthe first one. In this aspect, the offset in the first sub-element mayhave a fixed length (e.g., 13 bits) not depending on the indication1832. The offset in the first sub-element may indicate the identifier ofa paged STA, while the offset in the sub-elements other than the firstone may indicate a value equal to the identifier of the paged STA lessthe offset value indicated by the first element.

In some aspects, the DTIM period field 1820 or the bitmap control field1830 may include a sub-element length field (not shown). The sub-elementlength field may specify the bitmap length for some or all compressedTIM bitmap sub-elements included in field 1840. In one aspect, thesub-element length field may specify the individual bitmap length foreach of the some or all compressed TIM bitmap sub-elements.

FIG. 19 illustrates an exemplary frame format for a paging message 1900transmitted from the AP 104 to the STA 106. The paging message 1900 maybe similar to the paging message 302 a, 302 b, or 302 c. As shown, thepaging message 1900 includes an Information Element identification (IEID) field 1905, a LEN field 1910, a Delivery Traffic Indication Message(DTIM) count field 1915 and a DTIM period field 1920. Each of thesefields may have a size of 1 octet (byte).

Further, as shown, the paging message 1900 includes a compressed TIMbitmap field 1950 comprising multiple compressed TIM bitmapsub-elements. The size of field 1950 may be variable and may depend onthe method of compression that is used, as discussed below.

Compressed TIM bitmap field 1950 may comprise N pairs of fields 1951,each pair 1951 formed of sub-element control field 1955 and compressedsub-element field 1960, wherein N is the total number of compressed TIMbitmap sub-elements included in compressed TIM bitmap field 1950. Eachsub-element control field 1955 in a pair 1951 may comprise field 1956and field 1957. Field 1956 of pair 1951 is used to indicate the methodof compression used for compressing the TIM bitmap sub-element includedin field 1960 of the same pair 1951. Thus, a TIM bitmap sub-element maybe compressed with a method of compression that may be different fromthat used for compressing another TIM bitmap sub-element. In otherwords, the method of compression is applied per TIM bitmap sub-element.Nevertheless, in some scenarios it may occur that the same method ofcompression is used for all the TIM bitmap sub-elements. The exemplaryframe format 1900 would equally apply to such scenarios. The size offield 1956 may depend on the number of possible method of compressionsused for compressing the TIM bitmap sub-element 1960, in a similar wayas described above in relation to field 1831.

Field 1957 of pair 1951 may be used to indicate the length of the offsetfield when the offset compression method is employed for compressing theTIM bitmap sub-elements included in field 1960 of pair 1951. However, itis to be understood that field 1957 is not to be limited to a use inconjunction with the offset compression method as described above, butit may also be used for other compression methods that require, forexample, an indication of a length of an offset field. By way ofexample, and not limitation, the size of field 1957 may depend on thelength of the offset, for example up to 3 bits as shown in FIG. 19. Incertain aspects, field 1957 may be omitted.

In one aspect, field 1957 may be a field common to all the TIM bitmapsub-elements. Accordingly, field 1957 may be included directly and onlyonce into the paging message 1900, rather than being included for eachpair 1951. In other words, the length of the offset field is indicatedper TIM frame rather than per TIM bitmap sub-element. According to thisaspect, all TIM bitmap sub-elements 1960 that are compressed using theoffset compression method (or a compression method that may require anindication of an offset length) will use the same length of the offsetfield as indicated in the common field 1957. Moreover, according to thisaspect, the sub-element control field 1955 for each pair 1951 willcomprise only field 1956. One of the advantages of this aspect may be,for example, to further reduce the size of the compressed TIM bitmapfield 1950. In certain aspects, field 1957 may be omitted.

A TIM bitmap sub-element may correspond to a TIM bitmap sub-set of thecomplete TIM bitmap. A compressed TIM bitmap sub-element is a compressedversion of the TIM bitmap sub-element. Some of the possible methods ofcompression are illustrated below. By way of example, and notlimitation, the complete TIM bitmap may comprise clusters of ones. Basedon these clusters, the complete TIM bitmap may be split into differentbitmap sub-sets which are then compressed independently from each other.In one aspect, the TIM bitmap sub-element may include only a single bitcorresponding to a single STA 106. In certain aspects, these TIM bitmapsub-elements may correspond to groups of STAs as described above.

In some aspects, the DTIM period field 1920 or the sub-element controlfield 1955 may include a sub-element length field (not shown). Thesub-element length field may specify the bitmap length for some or allcompressed TIM bitmap sub-elements included in one or more fields 1960.In one aspect, the sub-element length field may specify the individualbitmap length for each of the some or all compressed TIM bitmapsub-elements.

FIG. 20 illustrates an exemplary frame format for a paging message 2000transmitted from the AP 104 to the STA 106. The paging message 2000 maybe similar to the paging message 302 a, 302 b, or 302 c. As shown, thepaging message 2000 includes an Information Element identification (IEID) field 2005, a LEN field 2010, a Delivery Traffic Indication Message(DTIM) count field 2015 and a DTIM period field 2020. Each of thesefields may have a size of 1 octet (byte).

Further, as shown, the paging message 2000 includes a compressed TIMbitmap field 2060 comprising multiple compressed TIM bitmap segments.The size of field 2060 may be variable and may depend on the method ofcompression that is used, as discussed below.

Compressed TIM bitmap field 2060 may comprise N pairs of fields 2061,each pair 2061 formed of segment control field 2070 and compressedsegment field 2080, wherein N is the total number of compressed TIMbitmap segments included in compressed TIM bitmap field 2060.

Each compressed segment field 2080 in a pair 2061 comprises K compressedTIM bitmap sub-elements 2081. All the TIM bitmap sub-elements 2081included in a compressed segment field 2080 may be compressed using thesame method of compression. By way of example, but not limitation, theuse of compressed segment fields and the information associated with thefields, as described, is useful when a TIM bitmap sub-element includesonly a single bit corresponding to a single STA 106.

Each segment control field 2070 in a pair 2061 may comprise field 2071,field 2072 and field 2073. Field 2071 of pair 2061 is used to indicatethe method of compression used for compressing the TIM bitmap segmentincluded in field 2080 of the same pair 2061. As described, all the TIMbitmap sub-elements 2081 included in a compressed segment field 2080 maybe compressed using the same method of compression. Thus, a TIM bitmapsegment may be compressed with a method of compression that may bedifferent from that used for compressing another TIM bitmap segment. Inother words, the method of compression is applied per TIM bitmapsegment. Nevertheless, in some scenarios, it may occur that the samemethod of compression is used for all the TIM bitmap segments. Theexemplary frame format 2000 would equally apply to such scenarios. Thesize of field 2071 may depend on the number of possible method ofcompressions used for compressing the TIM bitmap segment 2080, in asimilar way as described above in relation to field 1831.

Field 2072 of pair 2061 is used to indicate the number of TIMsub-elements 2081 included in TIM bitmap segment 2080 of pair 2061. In anon-limiting aspect, the size of field 2072 is 4 bits, thus allowing upto 16 TIM bitmap sub-elements per segment. Field 2073 of pair 2061 maybe used to indicate the length of the offset field when the offsetcompression method is employed for compressing the TIM bitmapsub-elements 2081 included in compressed segment field 2080 of pair2061. However, it is to be understood that field 2073 is not to belimited to a use in conjunction with the offset compression method asdescribed above, but it may also be used for other compression methodsthat require, for example, an indication of a length of an offset field.By way of example, and not limitation, the size of field 2073 may dependon the length of the offset, for example up to 3 bits as shown in FIG.20. In certain aspects, field 2073 may be omitted.

In one aspect, field 2073 may be a field common to all the TIM bitmapsegments. Accordingly, field 2073 may be included directly and only onceinto the paging message 2000, rather than being included for each pair2061. In other words, the length of the offset field is indicated perTIM frame rather than per TIM bitmap segment. According to this aspect,all TIM bitmap sub-elements 2081 that are compressed using the offsetcompression method (or a compression method that requires indication ofan offset length) will use the same length of the offset field asindicated in the common field 2073. Moreover, according to this aspect,the segment control field 2070 for each pair 2061 will comprise onlyfield 2071 and field 2072. One of the advantages of this aspect may be,for example, to further reducing the size of the compressed TIM bitmapfield 2060. In a non-limiting aspect, the bits not used by field 2073 ineach pair 2061 can be used field 2072. Thus, the size of field 2072 maybe 7 bits, thus allowing up to 128 TIM bitmap sub-elements per segment.In certain aspects, field 2073 may be omitted.

In some aspects, the DTIM period field 2020 or the segment control field2070 may include a sub-element length field (not shown) or segmentlength field (not shown). The sub-element length field may specify thebitmap length for one or more TIM bitmap sub-elements included in one ormore fields 2080. In one aspect, the sub-element length field mayspecify the individual bitmap length for each of the one or more TIMbitmap sub-elements. Further, the segment length field may specify thebitmap length for one or more pairs 2061.

FIG. 21 illustrates an exemplary frame format for a paging message 2100transmitted from the AP 104 to the STA 106. The paging message 2100 maybe similar to the paging message 302 a, 302 b, or 302 c. As shown, thepaging message 2100 includes an Information Element identification (IEID) field 2105, a LEN field 2110, a Delivery Traffic Indication Message(DTIM) count field 2115 and a DTIM period field 2120. Each of thesefields may have a size of 1 octet (byte).

Further, as shown, the paging message 2100 includes a compressed TIMbitmap field 2140 comprising multiple compressed TIM bitmapsub-elements. The size of field 2140 may be variable and may depend onthe method of compression that is used. Further, as shown, the pagingmessage 2100 may include a field 2130 that is used to indicate thelength of the offset field when the offset compression method (or acompression method that requires indication of an offset length) isemployed for compressing the TIM bitmap sub-elements. By way of example,and not limitation, the size of field 2130 may depend on the length ofthe offset, for example up to 3 bits as shown in FIG. 21.

In some aspects, the DTIM period field 2120 may include a sub-elementlength field (not shown). The sub-element length field may specify thebitmap length for some or all compressed TIM bitmap sub-elementsincluded in field 2140. In one aspect, the sub-element length field mayspecify the individual bitmap length for each of the some or allcompressed TIM bitmap sub-elements.

FIG. 22 is a flowchart of an exemplary process 2200 for wirelesscommunications. At block 2210, the AP 104 obtains at least one firstinformation sub-unit derived from a first information unit. In someaspects, the AP 104 may derive the at least one first informationsub-unit from the first information unit. The first information unit isassociated with a paging message. The at least one information sub-unitis arranged for processing by a first method of compression in order toobtain at least one first compressed information sub-unit. At block2220, the AP 104 compresses the at least one first information sub-unitwith a first method of compression associated with the at least onefirst information sub-unit. At block 2230, the AP 104 generates a secondinformation unit associated with the first method of compression. Atblock 2240, the AP 104 transmit a paging message including the at leastone first compressed information sub-unit and the second informationunit. It is to be understood that any of the above blocks may beperformed by an apparatus associated with AP 104. By way of example, butnot limitation, the at least one first compressed information unit maycorrespond to compressed elements 1840, 1960, 2080 and 2140 as describedabove, whereas the second information unit may correspond to controlelements 1830, 1955, 2070 and 2130, respectively.

FIG. 23 is a flowchart of an exemplary process 2300 for wirelesscommunications. Block 2310 corresponds to block 2210 as described above.Similarly, block 2320 and block 2330 correspond to block 2220 and block2230, respectively, as described above. At block 2340, the AP 104obtains at least one second information sub-unit derived from the firstinformation unit. In some aspects, the AP 104 derives the at least onesecond information sub-unit from the first information unit. The firstinformation unit is associated with the paging message. The at least oneinformation sub-unit is arranged for processing by a second method ofcompression in order to obtain at least one first compressed informationsub-unit. At block 2350, the AP 104 compresses the at least one secondinformation sub-unit with a second method of compression associated withthe at least one second information sub-unit. At block 2360, the AP 104generates a third information unit associated with the second method ofcompression. At block 2370, the AP 104 transmit a paging messageincluding the at least one first compressed information sub-unit, the atleast one second compressed information sub-unit, the second informationunit and the third information unit. It is to be understood that any ofthe above blocks may be performed by an apparatus associated with AP104. By way of example, but not limitation, the at least one firstcompressed information unit may correspond to compressed elements 1960and 2080 as described above, whereas the third information unit maycorrespond to control elements 1955 and 2070, respectively.

As intended herein, the word “information unit” encompasses a set ofdata associated with information (e.g., bits, bytes, or any othersuitable data). This set of data associated with information maycomprise one or more sub-sets of data associated with information,herein referred to as “information sub-units”. The cardinality of aninformation unit is defined as the number of sub-sets included in theset.

In some aspects, the bitmap may be compressed in order to obtain acompressed paging message. FIG. 24a illustrates an exemplary pagingmessage 2400 with a compressed bitmap, such as a traffic identificationmap (TIM) as described above. The paging message 2400 may be similar toany one of the paging messages 302 a, 302 b, or 302 c. As shown, thepaging message 2400 includes an EID field 2405, a LEN field 2410, acontrol field 2415, and one or more sub-bitmap elements 2420. Thecontrol field may indicate the type of compression used. The one or moresub-bitmap elements 2420 may be sent in a paging message within a singlepaging message in order to cover multiple STAs.

FIG. 24b illustrates the structure of one of sub-bitmap elements 2420.In particular, a first field 2421 indicates an offset value which isused to identify the index of a paged STA. In one aspect, the firstfield is formed of 13 bits. For example, the paged STA index may becomputed as a sum of the offset value and the bit position in thevariable-length bitmap 2423. A second field 2422 identifies the lengthof the variable-length bitmap 2423. The length is indicated in bytes. Inone aspect, the second field is formed of 3 bits. If the value of thelength is equal to zero, then the only STA that is paged is the STA withindex equal to the offset value contained in field 2421. If the value ofthe length is greater than zero, then the value of the length indicatesthe number of bytes in the variable-length bitmap 2423. A third field2423 identifies the variable-length bitmap. The variable-length bitmapis of variable length because trailing zeros can be omitted and assumedto be implicitly zeros (unless another sub-bitmap element 2420 indicatesotherwise). In one aspect, the length of the variable-length bitmap 2423can be from 0 bytes to 7 bytes. In another aspect, the value indicatedby the length field may be mapped to different lengths of the variablelength bitmap. For example, 0 may indicate that the variable length bitmap is not present, 1 may indicate that the variable length bitmap is 1byte, 2 may indicate that the variable length bitmap is 4 bytes, 3 mayindicate that the variable length is 8 bytes, etc.

FIG. 25a illustrates another exemplary paging message 2500 with acompressed bitmap, such as a traffic identification map (TIM) asdescribed above. By way of example, and not limitation, this pagingmessage 2500 can be used with a low-density bitmap (e.g., a bitmap inwhich the number of ones is greatly less than the number of zeros). Thepaging message 2500 may be similar to the paging message 302 b. Asshown, the paging message 2500 includes an EID field 2505, a LEN field2510, a control field 2515, and a compressed TIM Information Element(TIM IE) 2520. The control field may indicate the type of compressionused.

FIG. 25b illustrates the structure of the compressed TIM IE 2520. Thestructure employs running length sequences obtained by use of arunning-length encoding (RLE) method to process the original bitmap. Inparticular, a first field 2521 indicates the value of the first bit inthe sequence of a bitmap to be compressed. This value may be either “1”or “0”. A second field 2522 indicates the number N of running lengthsequences (e.g., N=2^(n), where n is the number of bits forming secondfield 2522). In one aspect, second field 2522 is formed of n=13 bits (inthis way, N can cover at least up to 6000). A third field 2523 indicatesthe number of bits L of each running length sequence (e.g., L=2^(l),where l is the number of bits forming third field 2523). In one aspect,third field 2523 is formed of l=4 bits. A fourth field 2524 includes therunning lengths sequences. The total number of bits forming fourth field2524 is N*L. In one aspect, the number of bits L can be selected asL=ceil(log₂ R), where R=max([r1, r2, . . . , rN]), with [r1, r2, . . . ,rN] corresponding to the sequence of the N running length sequences.From this compressed TIM IE, the STAs can losslessly reconstruct theoriginal bitmap.

FIG. 26 illustrates a method 2600 for compressing any one of the pagingmessages 302 a, 302 b, or 302 c. By way of example, and not limitation,possible compressed paging message 302 a, 302 b, or 302 c obtained bythis method are paging messages 1800, 1900, 2000, 2100, 2400 or 2500, asdescribed above. At block 2610, a transmitting device (e.g., the AP 104or an apparatus associated with the AP 104) schedules a plurality ofreceivers to be paged (e.g., the STAs 106). At block 2620, thetransmitting device generates a paging message; said paging messageidentifying one or more of the plurality of scheduled receivers. Atblock 2630, the transmitting device compresses the paging message.Various methods can be employed for performing the compression. At block2640, the transmitting device transmits the compressed paging message tothe one or more of the plurality of scheduled receivers. In certainsituations (e.g., by way of example, and not limitation, withhigh-density bitmap in which the number of zeros is much less than thenumber of ones) the transmitting device can choose a fraction (orsubgroup, or subset) of the plurality of receivers to be paged forinclusion in the paging message. The scheduling of the plurality ofdevices may be done, for example, in a round robin manner (not shown).The method 2600 as illustrated in FIG. 26 may coexist with any of themethods and processes discussed herein. Also, all or part of method 2600as illustrated in FIG. 26 may be combined with any of the methods orprocesses discussed herein.

FIG. 27a illustrates a method 2700 of compressing the paging message2400 as illustrated in FIG. 24a and FIG. 24b . At block 2705, thetransmitting device (e.g., the AP 104 or an apparatus associated withthe AP 104) defines a sub-bitmap element 2420. At block 2710 thetransmitting device inserts in sub-bitmap element 2420 informationdirected at identifying the index of a paged receiver (e.g., STA 106).The information can be, for example, in the form of fields 2421 and 2422as described above. At block 2715 the transmitting device inserts insub-bitmap element 2420 a variable-length bitmap 2423. At block 2720 thetransmitting device transmits one or more of sub-bitmap elements 2420 ina single paging message within a single TIM frame. This may be done inorder to cover multiple STAs within a single frame. The method of FIG.27a may coexist with any of the methods and processes discussed herein.By way of example, and not limitation, the method 2700 may include thecompression of block 2630 of method 2600 described herein.

FIG. 27b illustrates a method 2750 of compressing the paging message2500 as illustrated in FIG. 25a and FIG. 25b . At block 2755, thetransmitting device (e.g., the AP 104 or an apparatus associated withthe AP 104) receives a bitmap to be compressed. The bitmap may besimilar to the bitmap as described above. At block 2760, thetransmitting device compresses the bitmap by obtaining running-lengthsequences. The sequences can be obtained by using the well-knownrunning-length encoding (RLE) method. At block 2765, the transmittingdevice defines an information element, such as compressed TIM IE 2520.At block 2770, the transmitting device inserts in the informationelement as defined in block 2765 the running length sequences obtainedin block 2760. At block 2775, the transmitting device inserts in theinformation element as defined in block 2765 information relative to therunning length sequences obtained in block 2760. By way of example, andnot limitation, such information can comprise the information containedin field 2521, field 2522 and field 2523 as described above. Such methodcan be used, for example, with a low-density bitmap (e.g., a bitmap inwhich the number of ones is much less than the number of zeros).However, it is to be understood that this is not the only use, and theperson skilled in the art could use this method in any other suitablesituation.

FIG. 28 illustrates a method 2800 of receiving any one of compressedpaging messages 302 a, 302 b, or 302 c. By way of example, and notlimitation, possible compressed paging message 302 a, 302 b, or 302 creceived by this method are paging messages 1800, 1900, 2000, 2100, 2400or 2500, as described above. At block 2810, the receiver (e.g., STA 106)receives a compressed paging message from a transmitting device (e.g.,the AP 104 or an apparatus associated with the AP 104). At block 2820,the receiver reconstructs the original paging message from thecompressed paging message. The method of reconstructing the originalpaging message may depend on the method used for compressing saidoriginal paging message. At block 2830, the receiver selects a firstreceiver identifier from a plurality of receiver identifiers that areincluded in the original paging message. At block 2840, the receivertransmits a request to the transmitting device indicating selection ofthe first receiver identifier. The method 2800 as illustrated in FIG. 28may coexist with any of the methods and processes discussed herein.Also, all or part of method 2800 as illustrated in FIG. 28 may becombined with any of the methods or processes discussed herein.

In one aspect, the bitmap control field may include an ‘inverse bitmap’indication. The inverse bitmap indication may indicate whether thecompressed TIM bitmap is conveyed in a direct or inverse form. When theinverse bitmap indication indicates that the TIM bitmap is conveyed in adirect form, the TIM bitmap is compressed using any of the methodsdescribed herein. When the inverse bitmap indication indicates that theTIM bitmap is conveyed in an inverse form, the compressed TIM bitmapindicates the STAs 106 that are not paged. All the STAs 106 notindicated in the compressed TIM bitmap are paged STAs 106. One of thepossible advantages of having a direct form and an indirect form forconveying the compressed TIM bitmap is that, in certain situations, thenumber of STAs that are not paged is larger than the number of STAs thatare paged, and therefore the size of the compressed TIM bitmap may besmaller.

In one aspect, when the inverse bitmap indication indicates that the TIMbitmap is compressed in an inverse form, the TIM bitmap compression isperformed as follows. The lowest AID indicated in the paging messageindicates a first paged STA 106. All the STAs 106 with an AID lower thanthe lowest AID indicated in the paging message are assumed to be notpaged (first set of not paged STAs 106). The highest AID indicated inthe paging message indicates a second paged STA 106. All the STAs 106with an AID higher than the highest AID indicated in the paging messageare assumed to be not paged (second set of not paged STAs 106). All theSTAs 106 indicated in the paging message, excluding the ones with thelowest and highest AID, are not paged (third set of not paged STAs 106).Accordingly, the complete set of not paged STAs 106 is the union of thefirst set of not paged STAs 106, the second set of not paged STAs 106,and the third set of not paged STAs 106. All the STAs 106 that are notincluded in the complete set of not paged STAs 106 are paged STAs 106.For ease of processing, the STA with lowest AID may be indicated firstin the message and the STA with highest AID may be indicated last.

In another aspect, when the inverse bitmap indication indicates that theTIM bitmap is compressed in an inverse form, the TIM bitmap compressionis performed as follows. The lowest AID indicated in the paging messageindicates a first not paged STA 106. All the STAs 106 with an AID lowerthan the lowest AID indicated in the paging message are assumed to benot paged (first set of not paged STAs 106). The highest AID indicatedin the paging message indicates a second not paged STA 106, and all theSTAs 106 with an AID higher than the highest AID indicated in the pagingmessage are assumed to be not paged (second set of not paged STAs 106).All the STAs 106 indicated in the paging message, besides the ones withthe lowest and highest AID, are also not paged (third set of not pagedSTAs 106). Accordingly, the complete set of not paged STAs 106 is theunion of the first not paged STA 106, the second not paged STA 106, thefirst set of not paged STAs 106, the second set of not paged STAs 106,and the third set of not paged STAs 106. All the STAs 106 that are notincluded in the complete set of not paged STAs 106 are paged STAs 106.

In yet another aspect, when the inverse bitmap indication indicates thatthe TIM bitmap is compressed in an inverse form, the TIM bitmapcompression is performed as follows. The lowest AID indicated in thepaging message indicates a first paged STA 106. All the STAs 106 with anAID lower than the lowest AID indicated in the paging message areassumed to be not paged (first set of not paged STAs 106). The highestAID indicated in the paging message indicates a first not paged STA 106.All the STAs 106 with an AID higher than the highest AID indicated inthe paging message are assumed to be not paged (second set of not pagedSTAs 106). All the STAs 106 indicated in the paging message, besides theones with the lowest and highest AID, are not paged (third set of notpaged STAs 106). Accordingly, the complete set of not paged STAs 106 isthe union of the first not paged STA 106, the first set of not pagedSTAs 106, the second set of not paged STAs 106, and the third set of notpaged STAs 106. All the STAs 106 that are not included in the completeset of not paged STAs 106 are paged STAs 106.

In yet another aspect, when the inverse bitmap indication indicates thatthe TIM bitmap is compressed in an inverse form, the TIM bitmapcompression is performed as follows. The lowest AID indicated in thepaging message indicates a first not paged STA 106. All the STAs 106with an AID lower than the lowest AID indicated in the paging messageare assumed to be not paged (first set of not paged STAs 106). Thehighest AID indicated in the paging message indicates a first paged STA106. All the STAs 106 with an AID higher than the highest AID indicatedin the paging message are assumed to be not paged (second set of notpaged STAs 106). All the STAs 106 indicated in the paging message,besides the ones with the lowest and highest AID, are not paged (thirdset of not paged STAs 106). Accordingly, the complete set of not pagedSTAs 106 is the union of the first not paged STA 106, the first set ofnot paged STAs 106, the second set of not paged STAs 106, and the thirdset of not paged STAs 106. All the STAs 106 that are not included in thecomplete set of not paged STAs 106 are paged STAs 106.

FIG. 29 is a functional block diagram of an exemplary wireless device2900 that may be employed within the wireless communication system ofFIG. 1. The wireless device 2900 may include a deriving module 2905configured to derive a first information sub-unit from a firstinformation unit associated with a paging message. The deriving module2905 may be configured to perform one or more functions discussed abovewith respect to block 2210 of FIG. 22. The deriving module 2905 maycorrespond to processor 204. The wireless device 2900 may furtherinclude a compressing module 2910 configured to compress the firstinformation sub-unit according to a first method of compression toobtain a first compressed information sub-unit. The compressing module2910 may be configured to perform one or more functions discussed abovewith respect to block 2220 of FIG. 22. The compressing module 2910 maycorrespond to processor 204. The wireless device 2900 may furtherinclude a generating module 2915 configured to generate a secondinformation unit associated with the first method of compression. Thegenerating module 2915 may be configured to perform one or morefunctions discussed above with respect to block 2230 of FIG. 22. Thegenerating module 2915 may correspond to processor 204.

Moreover, in one aspect, means for deriving the first informationsub-unit may comprise the deriving module 2905. In another aspect, meansfor compressing the first information sub-unit may comprise thecompressing module 2910. In yet another aspect, means for generating thesecond information unit may comprise the generating module 2915.

As used herein, the term “determining” encompasses a wide variety ofactions. For example, “determining” may include calculating, computing,processing, deriving, investigating, looking up (e.g., looking up in atable, a database or another data structure), ascertaining and the like.Also, “determining” may include receiving (e.g., receiving information),accessing (e.g., accessing data in a memory) and the like. Also,“determining” may include resolving, selecting, choosing, establishingand the like. Further, a “channel width” as used herein may encompass ormay also be referred to as a bandwidth in certain aspects.

As used herein, a phrase referring to “at least one of” a list of itemsrefers to any combination of those items, including single members. Asan example, “at least one of: a, b, or c” is intended to cover: a, b, c,a-b, a-c, b-c, and a-b-c.

The various operations of methods described above may be performed byany suitable means capable of performing the operations, such as varioushardware and/or software component(s), circuits, and/or module(s).Generally, any operations illustrated in the Figures may be performed bycorresponding functional means capable of performing the operations.

The various illustrative logical blocks, modules and circuits describedin connection with the present disclosure may be implemented orperformed with a general purpose processor, a digital signal processor(DSP), an application specific integrated circuit (ASIC), a fieldprogrammable gate array signal (FPGA) or other programmable logic device(PLD), discrete gate or transistor logic, discrete hardware componentsor any combination thereof designed to perform the functions describedherein. A general purpose processor may be a microprocessor, but in thealternative, the processor may be any commercially available processor,controller, microcontroller or state machine. A processor may also beimplemented as a combination of computing devices, e.g., a combinationof a DSP and a microprocessor, a plurality of microprocessors, one ormore microprocessors in conjunction with a DSP core, or any other suchconfiguration.

In one or more aspects, the functions described may be implemented inhardware, software, firmware, or any combination thereof. If implementedin software, the functions may be stored on or transmitted over as oneor more instructions or code on a computer-readable medium.Computer-readable media includes both computer storage media andcommunication media including any medium that facilitates transfer of acomputer program from one place to another. A storage media may be anyavailable media that can be accessed by a computer. By way of example,and not limitation, such computer-readable media can comprise RAM, ROM,EEPROM, CD-ROM or other optical disk storage, magnetic disk storage orother magnetic storage devices, or any other medium that can be used tocarry or store desired program code in the form of instructions or datastructures and that can be accessed by a computer. Also, any connectionis properly termed a computer-readable medium. For example, if thesoftware is transmitted from a website, server, or other remote sourceusing a coaxial cable, fiber optic cable, twisted pair, digitalsubscriber line (DSL), or wireless technologies such as infrared, radio,and microwave, then the coaxial cable, fiber optic cable, twisted pair,DSL, or wireless technologies such as infrared, radio, and microwave areincluded in the definition of medium. Disk and disc, as used herein,includes compact disc (CD), laser disc, optical disc, digital versatiledisc (DVD), floppy disk and blu-ray disc where disks usually reproducedata magnetically, while discs reproduce data optically with lasers.Thus, in some aspects computer readable medium may comprisenon-transitory computer readable medium (e.g., tangible media). Inaddition, in some aspects computer readable medium may comprisetransitory computer readable medium (e.g., a signal). Combinations ofthe above should also be included within the scope of computer-readablemedia.

The methods disclosed herein comprise one or more steps or actions forachieving the described method. The method steps and/or actions may beinterchanged with one another without departing from the scope of theclaims. In other words, unless a specific order of steps or actions isspecified, the order and/or use of specific steps and/or actions may bemodified without departing from the scope of the claims.

The functions described may be implemented in hardware, software,firmware or any combination thereof. If implemented in software, thefunctions may be stored as one or more instructions on acomputer-readable medium. A storage media may be any available mediathat can be accessed by a computer. By way of example, and notlimitation, such computer-readable media can comprise RAM, ROM, EEPROM,CD-ROM or other optical disk storage, magnetic disk storage or othermagnetic storage devices, or any other medium that can be used to carryor store desired program code in the form of instructions or datastructures and that can be accessed by a computer. Disk and disc, asused herein, include compact disc (CD), laser disc, optical disc,digital versatile disc (DVD), floppy disk, and Blu-ray® disc where disksusually reproduce data magnetically, while discs reproduce dataoptically with lasers.

Thus, certain aspects may comprise a computer program product forperforming the operations presented herein. For example, such a computerprogram product may comprise a computer readable medium havinginstructions stored (and/or encoded) thereon, the instructions beingexecutable by one or more processors to perform the operations describedherein. For certain aspects, the computer program product may includepackaging material.

Software or instructions may also be transmitted over a transmissionmedium. For example, if the software is transmitted from a website,server, or other remote source using a coaxial cable, fiber optic cable,twisted pair, digital subscriber line (DSL), or wireless technologiessuch as infrared, radio, and microwave, then the coaxial cable, fiberoptic cable, twisted pair, DSL, or wireless technologies such asinfrared, radio, and microwave are included in the definition oftransmission medium.

Further, it should be appreciated that modules and/or other appropriatemeans for performing the methods and techniques described herein can bedownloaded and/or otherwise obtained by a user terminal and/or basestation as applicable. For example, such a device can be coupled to aserver to facilitate the transfer of means for performing the methodsdescribed herein. Alternatively, various methods described herein can beprovided via storage means (e.g., RAM, ROM, a physical storage mediumsuch as a compact disc (CD) or floppy disk, etc.), such that a userterminal and/or base station can obtain the various methods uponcoupling or providing the storage means to the device. Moreover, anyother suitable technique for providing the methods and techniquesdescribed herein to a device can be utilized.

It is to be understood that the claims are not limited to the preciseconfiguration and components illustrated above. Various modifications,changes and variations may be made in the arrangement, operation anddetails of the methods and apparatus described above without departingfrom the scope of the claims.

While the foregoing is directed to aspects of the present disclosure,other and further aspects of the disclosure may be devised withoutdeparting from the basic scope thereof, and the scope thereof isdetermined by the claims that follow.

What is claimed is:
 1. An apparatus for wireless communicationcomprising: a processor configured to: generate a first informationsub-unit, the first information sub-unit including a bitmap having aplurality of bits, at least one of the plurality of bits indicating thatthe apparatus has data buffered to transmit to a first wireless deviceof a plurality of wireless devices, compress the first informationsub-unit according to a first method of compression to obtain a firstcompressed information sub-unit, and generate a second information unitassociated with the first method of compression; and a transceiverconfigured to transmit a paging message, the paging message includingthe first compressed information sub-unit and the second informationunit.
 2. The apparatus of claim 1, wherein the paging message comprisesa sub-unit length field configured to indicate a length of the firstcompressed information sub-unit.
 3. The apparatus of claim 1, whereinthe first information sub-unit is derived from a first information unit,and the processor is further configured to: derive a second informationsub-unit from the first information unit; compress the secondinformation sub-unit according to a second method of compression toobtain a second compressed information sub-unit; and generate a thirdinformation unit associated with the second method of compression. 4.The apparatus of claim 3, wherein the paging message includes the firstcompressed information sub-unit, the second compressed informationsub-unit, the second information unit, and the third information unit.5. The apparatus of claim 3, wherein the first method of compression isthe same as the second method of compression.
 6. The apparatus of claim3, wherein the second information unit includes an identification of thefirst method of compression.
 7. The apparatus of claim 3, wherein thesecond information unit includes an indication of an offset sizeassociated with the first compression method, the offset size indicatingan identifier of the first wireless device.
 8. The apparatus of claim 3,wherein the second information unit includes an indication of acardinality associated with the first information unit.
 9. The apparatusof claim 3, wherein the paging message comprises a sub-unit length fieldconfigured to indicate an individual length of the first compressedinformation sub-unit and the second compressed information sub-unit. 10.A method of wireless communications comprising: generating a firstinformation sub-unit, the first information sub-unit including a bitmaphaving a plurality of bits, at least one of the plurality of bitsindicating that an access point has data buffered to transmit to a firstwireless device of a plurality wireless devices; compressing the firstinformation sub-unit according to a first method of compression toobtain a first compressed information sub-unit; generating a secondinformation unit associated with the first method of compression; andtransmitting a paging message, the paging message including the firstcompressed information sub-unit and the second information unit.
 11. Themethod of claim 10, wherein the paging message comprises a sub-unitlength field configured to indicate a length of the first compressedinformation sub-unit.
 12. The method of claim 10, wherein the firstinformation sub-unit is derived from a first information unit, themethod further comprising: deriving a second information sub-unit fromthe first information unit, the second information sub-unit indicatingthat the access point has data buffered to transmit to at least a secondwireless device of the plurality of wireless devices; compressing thesecond information sub-unit according to a second method of compressionto obtain a second compressed information sub-unit; and generating athird information unit associated with the second method of compression.13. The method of claim 12, wherein the paging message includes thefirst compressed information sub-unit, the second compressed informationsub-unit, the second information unit, and the third information unit.14. The method of claim 12, wherein the first method of compression isthe same as the second method of compression.
 15. The method of claim12, wherein the second information unit includes an identification ofthe first method of compression.
 16. The method of claim 12, wherein thesecond information unit includes an indication of an offset sizeassociated with the first method of compression, the offset sizeindicating an identifier of the first wireless device.
 17. The method ofclaim 12, wherein the second information unit includes an indication ofa cardinality associated with the first information unit.
 18. The methodof claim 12, wherein the paging message comprises a sub-unit lengthfield configured to indicate an individual length of the firstcompressed information sub-unit and the second compressed informationsub-unit.
 19. An apparatus for wireless communication comprising: meansfor generating a first information sub-unit, the first informationsub-unit including a bitmap having a plurality of bits, at least one ofthe plurality of bits indicating that the apparatus has data buffered totransmit to a first wireless device of a plurality of wireless devices;means for compressing the first information sub-unit according to afirst method of compression to obtain a first compressed informationsub-unit; means for generating a second information unit associated withthe first method of compression; and means for transmitting a pagingmessage, the paging message including the first compressed informationsub-unit and the second information unit.
 20. A non-transitorycomputer-readable medium comprising instructions that when executedcause an apparatus to: generate a first information sub-unit, the firstinformation sub-unit including a bitmap having a plurality of bits, atleast one of the plurality of bits indicating that an access point hasdata buffered to transmit to a first wireless device of a plurality ofwireless devices; compress the first information sub-unit according to afirst method of compression to obtain a first compressed informationsub-unit; generate a second information unit associated with the firstmethod of compression; and transmit a paging message, the paging messageincluding the first compressed information sub-unit and the secondinformation unit.
 21. The apparatus of claim 1, further comprising amemory configured to store the first compressed information sub-unit andthe second information unit.
 22. The apparatus of claim 1, wherein thefirst method of compression is based on one or more sequential bits inthe bitmap having a same bit value.